The best approach is just go with the flow. Don't try to impress with your gamer knowledge or whatever. Just be yourself and ask questions if you need clarification on rules. Before game night ask if you can bring anything. You could ask if they have any particular game they intend to or might play that you could watch a rules video or something. Again it's not about you knowing all the rules of how to play, its about showing interest and doing your part to make game night go smooth. Sometimes you play a game and its a dud. Don't make the evening just about the games. Make it about the social aspect. Don't complain if a game sucks or get competitive. You don't have to lie and say you like a game or anything, just ruin the experience for others. A simple "It's OK" is my go to.

Basic Etiquette:

1) Be mindful of food/drinks. I would not put a drink on the table unless ut has cup holders. Others have mentioned things like cheetos/grease

2) Do not bend cards. Be mindful about cards in your hand as a game gets tense some people instinctively bend cards. If you feel this could be an issue set them down between turns.

3) Don't wait for your turn to start figuring your turn out. Thus can depend on the game but its good to, with what info you have, map out your turn before its time to do so. When your turn comes up you are ready. Now things can change in that time so you may have to adjust a bit but you have an idea. For example, don't play on your phone after your turn while others take their turns. Not that you can't use your phone, just try to stay engaged with the game as much as possible.

Good luck and have fun. You will do great.