You leave your elbows off the dinner table and understand the importance of a nice, firm handshake. Congrats! You’re a generally well-mannered person. But do you know which hand you should wave with? Or which seat to offer your boss in the back of a town car? There are tons of little-known etiquette rules that most people break every single day. Etiquette expert Joy Weaver, author of How to Be Socially Savvy in All Situations, lets us in on the 10 most common blunders—and provides a crash course on being proper.

1. You’re coughing into your right hand.

Covering your mouth when you sneeze or cough is good manners. Using your right hand to do it? That’s bad. “Your right hand is your social hand,” Weaver says. “It should be available for shaking hands, waving, and blowing kisses.” Your left hand, meanwhile, is what she dubs your “personal” hand: “That’s the hand you use for coughing, scratching, sneezing, whatever it is we don’t want to talk about.” The reason for the distinction, she explains, is simple politeness—you don’t want to sneeze into one hand, then absentmindedly use that palm to shake hands with a new colleague.

2. You’re wearing your handbag on your right shoulder—and slinging it over the back of your chair.

To keep your “social” hand free for greetings, it’s best to keep your handbag — or cocktail! — in your left hand. That way, says Weaver, “you don’t have to take the time to switch it over to the other arm when you’re reaching out to shake someone’s hand.” (Of note: Queen Elizabeth always keeps her tote on her left.) While you’re at it, never place your handbag on the back of a chair when you’re seated at a table. The proper spot, says Weaver, is on the floor to your right.

3. Also, you’re calling it a “purse.”

That term is reserved for any clutch, tote, satchel, etc. that costs less than $100. “A purse is something that is relatively inexpensive,” notes Weaver. “A handbag is more expensive. You should never go into Neiman Marcus and ask for their purse department. They don’t have one.”

4. You’re sitting down wrong.

To avoid collisions at the dinner table, always approach your chair from the left-hand side and exit on the right, says Weaver. And if you need to use the restroom during the meal, never announce your intentions to the group. Suggests the pro, “Just say, ‘Excuse me,’ and step away.”

5. You’re passing the salt without the pepper.

“They’re like a little couple,” Weaver says of the salt-and-pepper shakers. “You never want to separate them.” The theory: even if one diner asks only for the salt, the person next to them may want both, so they should be kept together. And remember—always pass to the right!

6. You’re applauding incorrectly.

Study celebrities at any major awards show: not everyone is properly recognizing the winners. The correct way to applaud is just slightly to your left, about chest height. Says Weaver, “You never want to clap in front of your own face and you sure don’t want to clap in front of someone else’s.”

7. You’re claiming the best seat in the car …

The power seat in any limo is to the back and the right. That’s the one you should leave for your boss “or whomever is the person of prominence or honor,” says Weaver. The next person in line gets to claim the seat to the left, while the junior person usually gets the middle. (Note: the same does not apply to riding with your siblings.)

8. … And you’re climbing in wrong.

When entering a vehicle, first sit down, then swing your legs in. “It’s the appropriate way to do it,” says Weaver. “And it’s classy.” As an added bonus, it prevents any skirt-wearing ladies from accidentally flashing their companions.

9. You’re pointing at your friend.

“We can point at something,” says Weaver, “but we never point at someone. If you must point out across the room to your pal, you may gesture, but be sure to use an open hand."

10. You’re using a revolving door improperly.

Holding the door? You’ve got that one down. But when faced with a revolving door, it's polite to enter first. Explains the pro, “You never want your client or date to have to push while you’re behind them just prancing in. It’s about making the other person feel special and making it easier on them.” What it isn’t about, she says, is showing off. “It should never be, ‘How about me, I know all of these things,’” notes Weaver. Because being a braggart—well, that’s just rude.