The worst mistakes I made at a convention...
1.) feeling shy.
People don't often bite at conventions. Don't get stuck in your room. Don't be a wall flower. Sure, if you walk up to folks in the bar and stand there silent like a creeper, you're probably going to get a cold shoulder. That's why you start at the panels. Polite chatting with those around you before the panel starts (Hey, have you read anything by these panelists? Who's your favorite authors? etc.) and you make an impression of friendly. When the day is done, you have a slew of friendly faces to approach with a simple smile and a "Can I join you?"
2.) the wrong shoes.
I've said it before. It's stupid, I know, but seriously, you think, panels = sitting. You're just walking from your room to a panel room, then another panel room...right? Those gorgeous shoes you haven't broken in yet look great and it'll be ok. Could be. But if you're lucky you've chatted with folks (see above) you get to go to lunch with some fabulous people and talk, network, etc. and THAT usually involves lots of walking. Now, understand, I'm not a tender-footed crybaby. Being part hillbilly (the better part, perhaps) I'm down with taking the shoes off and goin' barefoot to make sure that my mind is focused on the conversation the people and the networking rather than ouch, ouch, ouch. But if the whole idea is to be professional and have fun, comfy footwear is important...and, truly, barefootin' it may not be the impression you were goin' for.
3.) the wrong con.
I have an Urban Fantasy series. Romance cons really don't get it, IMHO. I wasted a lot of money going to Romance cons when the series was new. But I had a lot of fun. My WIP is just Fantasy. The con's listed below are more suitable for my work.
My con schedule this fall:
DragonCon, Labor Day Weekend, Atlanta GA
Context, Sept 26-28, Columbus OH
World Fantasy Convention, Early November, Washington D.C.