Screw that! go to ComicCon!
The trick to cosplay photos. Just smile and get their attention. They'll give you the go ahead to take pictures. Get CLOSE! Offer your contact info or get theirs so that you can send the pictures. If the lighting is bad, get them to move to a place where the lighting and background works. If you're not familiar with the character being portrayed, just ask. Cosplayers are the friendliest most awesome people.
Please number your photos. It helps us refer to them more easily.
I love the Companion Cube photo! Good DOF and comp, imo. Also zombie nurse (dunno who she is) has a lot of creepy feeling and fun. Nice lens flare in #1
It's like Halloween, but not October, and not dark out! Awesomeness, I need to find something like that to go wield a camera at, none of my wedding clients dress quite that cool.