1. Want a cosplayer's picture? Ask before you snap.
I'm a huge fan of candid photography, but cosplayers poses are too good to pass up. People love to act like their characters, which makes for great pictures.
2. Find areas with natural light sources.
The Convention Center's big windows give off wonderful diffused light. The registration hallway is a popular photo spot boasting balanced, ambient light. Plus it's full of newcomer cosplayers who aren't yet tired of posing for photos. The convention center's cavernous hallways and panel rooms make for poor photos.
3. Tag and post your photos quickly.
I posted my Comic Con photos to Flickr last Monday night, one day after Comic Con ended. With minimal tagging and promotion, each photo averaged a couple hundred views by the following day. For an album with 60 photos, that's a total view count near 10,000. I'm confident that those who posted during The Con fared much better. Views dropped off significantly in the following days, as Comic Con became last week's news.