Replying to Shooting Sr. Pictures soon. need critiquing!

I posted this in Media & Arts but it didn't receive much feedback.

First off, I'm decently new to this t2i I recently picked up but I've agreed to help out a few friends with their sr. pictures.

Set up:
body- t2i
lenses- 18-55mm and 50mm f1.8
(I know, its not that next level stuff)

Here is my flikr:
http://www.flickr.com/photos/thetranclancollabo/

If there is any advice you could give me as to what setting to shoot on like "AV" and custom white balance tips, that would be rad. Anything other critiquing, just spit it out. I can take it.

Thanks