My first comic con was NYCC 2009. I was working for Activision at the time and the whole team was buried in overtime working on MUA2 and as a surprise reward they sent the whole dev team to NYCC travel included. We got in on Wednesday with vendor passes as back then Wednesday was vendors and vip passes only. It was a blast and we got to meet a lot of really great people. Since that year I have been lucky enough to get passes to go every year.
It was a really memorable year because it was such a great company present and introduced me to something I would have never done on my own. It was also the only year I went as a company representative which was also a lot of fun. Since then the con has blown up and this past year it beat SDCC in attendance making it the largest one that year.
I would recommend taking a look at the panel list early and pick what you can't miss and a few things you can miss. Sometimes a panel you are only half interested in is a great idea to rest your feet as the concrete floor of the venue can be a killer.
I would also recommend setting a meeting point and a time to meet then spending a couple hours on your own just doing what you want where you are not pressured by friends to move on too fast when you see something your interested in.
Cosplay is awesome just please remember cosplay is not concent for pictures or anything else. You can definitely take tons of cosplay pictures just ask first. Most everyone will say yes and pose for you, if they don't let them be, its a crazy day for anyone in cosplay and sometimes you need a break.
This year I may even cosplay for the first time with my sabers if I can get it together
The most important thing is to have fun.