Etiquette isn't about rules. It's about making other people feel comfortable. Once you understand that, most of it becomes obvious.
The Basics Still Matter
Eye contact. A firm handshake. Putting your phone away when someone is talking to you. Arriving on time. Saying thank you and meaning it. These aren't old-fashioned. They're signals that you respect the people around you.
A note on cultural differences: in most of the Western world, a firm handshake is the default greeting. In Japan, a bow. In parts of Southern Europe and Latin America, a kiss on the cheek. The specifics don't matter as much as the intent: acknowledge the person in front of you, on their terms.
At the Table
Wait for everyone to be served before eating. Keep your elbows off the table when you're eating. It's about posture and presence, not an arbitrary rule. At a formal dinner, start with the outermost fork and work your way in. Nobody will notice if you do it calmly. And mind where the bread goes: your bread plate is on the left, your water glass is on the right.
In South India, eating with your right hand is traditional and entirely proper. In much of East Asia, slurping noodles is a sign of appreciation, not rudeness. What's considered polite is shaped by where you are. Know your context.
Burping at the table is one of those things that varies wildly by culture. In some parts of the world it signals satisfaction. In most Western social situations it doesn't. When in doubt, err on the side of discretion.
Phones at dinner deserve their own mention. Unless there's a genuine emergency, face down or out of sight. The message you send by checking your phone mid-conversation isn't subtle.
On the Sidewalk
This one gets overlooked. When walking with someone on a city sidewalk, the traditional rule is for the man to walk on the street side, originally to protect against splashing from horse-drawn carriages. In New York and other cities with window air conditioning units overhead, the more practical version is: walk on whichever side shields your companion from the drip. In cities like Mumbai or Chennai where monsoon roads have serious standing water and passing vehicles can drench a pedestrian, it matters even more. Pay attention to your environment. Walk on the side that takes the hit, not the one that's convenient.
On revolving doors: the gentleman goes in first, pushing the door so the other person doesn't have to do the work. It looks counterintuitive but it's the right move.
And while we're on New York specifically: the subway has its own code. Take your backpack off on a crowded train (or elevator). Don't play music out loud, not everyone wants to hear it. Don't game loudly or talk on speakerphone. Move to the center of the car. Don't stop at the bottom of the stairs or the entrance to the platform while you check your phone. And don't walk three across on a narrow sidewalk at a leisurely pace. The city moves. Move with it.
Drinking and Cigars
Pour for others before yourself. Don't pressure anyone to drink more than they want. At a cigar lounge, ask before lighting up near someone who hasn't. Blow smoke away from people. Ash when the ash gets long, not at the last moment.
How You Dress
Dressing appropriately for the occasion isn't about vanity. It shows you understood where you were going and respected it enough to prepare. Overdressing is generally better than underdressing. You can always remove a jacket.
Conversation
Listen more than you talk. Ask follow-up questions. Don't interrupt. Avoid talking about money unprompted, what things cost, what you earn, what others should be spending. It makes people uncomfortable.
Opening a door for someone costs nothing. Holding the elevator. Letting someone merge in traffic. These aren't grand gestures. They're the texture of how you move through the world.
The goal isn't to perform good manners. It's to be the kind of person people enjoy being around. Most of that comes down to paying attention.
When you see someone commit a social blunder, the gracious move is to let it go. Don't draw attention to it. Don't make eye contact with others about it. If it directly affects you, a quiet, private word is always better than a public correction. Most people know when they've slipped up. They don't need an audience. Giving someone a dignified exit is one of the most underrated acts of good manners there is.