Hey guys! I went to NYLC last month and I had a BLAST! Here's some tips from my experience.
1. BRING SNACKS! Like Cheeze its, granola bars, juice boxes etc. because hotel food isn't so good. There will be many days where you come back into your room and be STARVING. You will be thankful when you get to go out for lunch or dinner.
2. Girls, don't bring too many clothes. You have to share a closet with two other girls. My best advice would be to bring lots of items that you can mix and match with others. Laundry can be done through the hotel, but it's like ten dollars. Or at least at the Sheraton it was.
3. Get to know the people in your LGMs and Model Congress groups. Your LGM is basically your family away from home. It's amazing how close of a bond you form with these people. On the last day it's SOO hard to say goodbye. Model Congress is another family in a way, but you're not nearly with them as much as you are with LGM.
4. KEEP AN OPEN MIND. If something sounds stupid, and you keep thinking it will be, then it will be. You won't learn anything. But if you keep and open mind, you will be surprised with what you learn.
5. Don't be afraid to talk to other kids. They're all just as nervous on the first day as you are

So the first couple of days, go sit with a different table everyday.
6. Be prepared for people to ask you what NYLC is. You will have that nametag on everywhere you go and there's like 300 something kids, so people want to know.
7. Step out of your comfort zone.
8. Wear the NICEST thing you have the day you go on Capital Hill. You don't want to look like a mess.
9. Take LOTS and LOTS of pictures, you'll thank yourself later!
10. Last but not least, ENJOY EVERY MOMENT! The ten days go by so fast.
Hope my advice helps!