More from
THE GENTLEMEN’S BOOK OF ETIQUETTE, AND MANUAL OF POLITENESS

This section is quoted from an English Lawyer.
Good advice actually.
Keep your sightglass full, your firebox trimmed and your water iced.
KJ

A celebrated English lawyer gives the following directions for young men entering into business. He says:—
“Select the kind of business that suits your natural inclinations and temperament.—Some men are naturally mechanics; others have a strong aversion to anything like machinery, and so on; one man has a natural taste for one occupation in life, and another for another.

“I never could succeed as a merchant. I have tried it, unsuccessfully, several times. I never could be content with a fixed salary, for mine is a purely speculative disposition, while others are just the reverse; and therefore all should be careful to select those occupations that suit them best.

“Let your pledged word ever be sacred.—Never promise to do a thing without performing it with the most rigid promptness. Nothing is more valuable to a man in business than the name of always doing as he agrees, and that to the moment. A strict adherence to this rule gives a man the command of half the spare funds within the range of his acquaintance, and encircles him with a host of friends, who may be depended upon in any emergency.

“Whatever you do, do with all your might.—Work at it, if necessary, early and late, in season and out of season, not leaving a stone unturned, and never deferring for a single hour that which can just as well be done now. The old proverb is full of truth and meaning—“Whatever is worth doing at all, is worth doing well.” Many a man acquires a fortune by doing his business thoroughly, while his neighbor remains poor for life, because he only half does his business. Ambition, energy, industry, and perseverance, are indispensable requisites for success in business.

“Sobriety. Use no description of intoxicating drinks.—As no man can succeed in business unless he has a brain to enable him to lay his plans, and reason to guide him in their execution, so, no matter how bountifully a man may be blessed with intelligence, if his brain is muddled, and his judgment warped by intoxicating drinks, it is impossible for him to carry on business successfully. How many good opportunities have passed never to return, while a man was sipping a ‘social glass’ with a friend! How many a foolish bargain has been made under the influence of the wine-cup, which temporarily makes his victim so rich! How many important chances have been put off until to-morrow, and thence for ever, because indulgence has thrown the system into a state of lassitude, neutralizing the energies so essential to success in business. The use of intoxicating drinks as a beverage is as much an infatuation as is the smoking of opium by the Chinese, and the former is quite as destructive to the success of the business man as the latter.

“Let hope predominate, but be not too visionary.—Many persons are always kept poor because they are too visionary. Every project looks to them like certain success, and, therefore, they keep changing from one business to another, always in hot water, and always ‘under the harrow.’ The plan of ‘counting the chickens before they are hatched,’ is an error of ancient date, but it does not seem to improve by age.

“Do not scatter your powers.—Engage in one kind of business only, and stick to it faithfully until you succeed, or until you conclude to abandon it. A constant hammering on one nail will generally drive it home at last, so that it can be clinched. When a man’s undivided attention is centered on one object, his mind will continually be suggesting improvements of value, which would escape him if his brain were occupied by a dozen different subjects at once. Many a fortune has slipped through men’s fingers by engaging in too many occupations at once.

“Engage proper employees.—Never employ a man of bad habits when one whose habits are good can be found to fill his situation. I have generally been extremely fortunate in having faithful and competent persons to fill the responsible situations in my business; and a man can scarcely be too grateful for such a blessing. When you find a man unfit to fill his station, either from incapacity or peculiarity of character or disposition, dispense with his services, and do not drag out a miserable existence in the vain attempt to change his nature. It is utterly impossible to do so, ‘You cannot make a silk purse,’ &c. He has been created for some other sphere; let him find and fill it.”

A Guide for Gentlemen
This section covers the thorny issue of how to behave at plays and musical venues taken from:
THE GENTLEMEN’S BOOK OF ETIQUETTE, AND MANUAL OF POLITENESS

 ETIQUETTE FOR PLACES OF AMUSEMENT.

When you wish to invite a lady to accompany you to the theatre, opera, a concert, or any other public place of amusement, send the invitation the day previous to the one selected for taking her, and write it in the third person. If it is the first time you have invited her, include her mother, sister, or some other lady in the invitation.

If she accepts your invitation, let it be your next care to secure good seats, for it is but a poor compliment to invite a lady to go to the opera, and put her in an uncomfortable seat, where she can neither hear, see, nor be seen.

Although, when alone, you will act a courteous part in giving your seat to a strange lady, who is standing, in a crowded concert room, you should not do so when you are with a lady. By giving up your place beside her, you may place a lady next her, whom she will find an unpleasant companion, and you are yourself separated from her, when the conversation between the acts makes one of the greatest pleasures of an evening spent in this way. In case of accident, too, he deprives her of his protection, and gives her the appearance of having come alone. Your first duty, when you are escorting a lady, is to that lady before all others.

When you are with a lady at a place of amusement, you must not leave your seat until you rise to escort her home. If at the opera, you may invite her to promenade between the acts, but if she declines, do you too remain in your seat.

Let all your conversation be in a low tone, not whispered, nor with any air of mystery, but in a tone that will not disturb those seated near you.

Any lover-like airs or attitudes, although you may have the right to assume them, are in excessively bad taste in public.

If the evening you have appointed be a stormy one, you must call for your companion with a carriage, and this is the more elegant way of taking her even if the weather does not make it absolutely necessary.

When you are entering a concert room, or the box of a theatre, walk before your companion up the aisle, until you reach the seats you have secured, then turn, offer your hand to her, and place her in the inner seat, taking the outside one yourself; in going out, if the aisle is too narrow to walk two abreast, you again precede your companion until you reach the lobby, where you turn and offer your arm to her.

Loud talking, laughter, or mistimed applause, are all in very bad taste, for if you do not wish to pay strict attention to the performance, those around you probably do, and you pay but a poor compliment to your companion in thus implying her want of interest in what she came to see.

A guide for gentlemen.
This guide is excerpted from:

THE GENTLEMEN’S BOOK OF ETIQUETTE, AND MANUAL OF POLITENESS;
by Cecil B. Hartley, published in 1860 in Boston.

This book has tons of interesting information on how a "Gentleman" should behave. Everything from dress and wedding etiquette to letter writing and how to behave at public "amusements".  While much of this seems quaint in today's free and easy world, I think we would do well to remember that many of these rules were necessary in the crowded pedestrian cities of the 19th century.

The One Hundred Hints below have some insights into what it means to be a Gentlemen regardless of what one's station in society was.  I have copied the whole section for ease of reference so my apologies for the length.
Enjoy

Keep your sightglass full, your firebox trimmed and your water iced.
KJ 

ONE HUNDRED HINTS FOR GENTLEMANLY DEPORTMENT.

1. Always avoid any rude or boisterous action, especially when in the presence of ladies. It is not necessary to be stiff, indolent, or sullenly silent, neither is perfect gravity always required, but if you jest let it be with quiet, gentlemanly wit, never depending upon clownish gestures for the effect of a story. Nothing marks the gentleman so soon and so decidedly as quiet, refined ease of manner.

2. Never allow a lady to get a chair for herself, ring a bell, pick up a handkerchief or glove she may have dropped, or, in short, perform any service for herself which you can perform for her, when you are in the room. By extending such courtesies to your mother, sisters, or other members of your family, they become habitual, and are thus more gracefully performed when abroad.

3. Never perform any little service for another with a formal bow or manner as if conferring a favor, but with a quiet gentlemanly ease as if it were, not a ceremonious, unaccustomed performance, but a matter of course, for you to be courteous.

4. It is not necessary to tell all that you know; that{187} were mere folly; but what a man says must be what he believes himself, else he violates the first rule for a gentleman’s speech—Truth.

5. Avoid gambling as you would poison. Every bet made, even in the most finished circles of society, is a species of gambling, and this ruinous crime comes on by slow degrees. Whilst a man is minding his business, he is playing the best game, and he is sure to win. You will be tempted to the vice by those whom the world calls gentlemen, but you will find that loss makes you angry, and an angry man is never a courteous one; gain excites you to continue the pursuit of the vice; and, in the end you will lose money, good name, health, good conscience, light heart, and honesty; while you gain evil associates, irregular hours and habits, a suspicious, fretful temper, and a remorseful, tormenting conscience. Some one must lose in the game; and, if you win it, it is at the risk of driving a fellow creature to despair.

6. Cultivate tact! In society it will be an invaluable aid. Talent is something, but tact is everything. Talent is serious, sober, grave, and respectable; tact is all that and more too. It is not a sixth sense, but it is the life of all the five. It is the open eye, the quick ear, the judging taste, the keen smell, and the lively touch; it is the interpreter of all riddles—the surmounter of all difficulties—the remover of all obstacles. It is useful in all places, and at all times; it is useful in solitude, for it shows a man his way into the world; it is useful in society, for it shows him his way through the world. Talent is power—tact is skill; talent is weight—tact is momentum; talent knows what to do—tact knows how to do it;{188} talent makes a man respectable—tact will make him respected; talent is wealth—tact is ready money. For all the practical purposes of society tact carries against talent ten to one.

7. Nature has left every man a capacity of being agreeable, though all cannot shine in company; but there are many men sufficiently qualified for both, who, by a very few faults, that a little attention would soon correct, are not so much as tolerable. Watch, avoid such faults.

8. Habits of self-possession and self-control acquired early in life, are the best foundation for the formation of gentlemanly manners. If you unite with this the constant intercourse with ladies and gentlemen of refinement and education, you will add to the dignity of perfect self command, the polished ease of polite society.

9. Avoid a conceited manner. It is exceedingly ill-bred to assume a manner as if you were superior to those around you, and it is, too, a proof, not of superiority but of vulgarity. And to avoid this manner, avoid the foundation of it, and cultivate humility. The praises of others should be of use to you, in teaching, not what you are, perhaps, but in pointing out what you ought to be.

10. Avoid pride, too; it often miscalculates, and more often misconceives. The proud man places himself at a distance from other men; seen through that distance, others, perhaps, appear little to him; but he forgets that this very distance causes him also to appear little to others.

11. A gentleman’s title suggests to him humility and affability; to be easy of access, to pass by neglects and{189} offences, especially from inferiors; neither to despise any for their bad fortune or misery, nor to be afraid to own those who are unjustly oppressed; not to domineer over inferiors, nor to be either disrespectful or cringing to superiors; not standing upon his family name, or wealth, but making these secondary to his attainments in civility, industry, gentleness, and discretion.

12. Chesterfield says, “All ceremonies are, in themselves, very silly things; but yet a man of the world should know them. They are the outworks of manners, which would be too often broken in upon if it were not for that defence which keeps the enemy at a proper distance. It is for that reason I always treat fools and coxcombs with great ceremony, true good breeding not being a sufficient barrier against them.”

13. When you meet a lady at the foot of a flight of stairs, do not wait for her to ascend, but bow, and go up before her.

14. In meeting a lady at the head of a flight of stairs, wait for her to precede you in the descent.