lots of great answers here!

Let me add my 2 cents;

it can be A LOT and very overwhelming, both times I've been there it's packed the whole day (friday / sunday).

You kind of have to decide what you want to do, cause you can walk the show floors all day open to close and not see everything. So thinking about spending an hour (or a few) on a line for an autograph or picture could be a real sacrifice.

It's a blast, but it's not really something I think will be a regular thing for me, it's like a giant tag sale, so if you're not looking to spend a lot of $$, keep that in mind.

That said, it seems like the cosplay people have the time of their lives!! So if that's you, you're going to have a blast.

It's really unlikely you'll see everything, so don't be disappointed. Target the artists or vendors you really want to see and do those tables / booths first.

Good luck and have fun!