Reddit reviews The Photographer's Eye: Composition and Design for Better Digital Photographs

"The Photographer's Eye" has been suggested quite a few times here, for good reason I think. Quite enjoyable and informative.

There are a few things you can get without much info; but it'd help if you know what sort of things he likes to shoot (and where - indoor, outdoor), as well as how long he's been shooting for! (If he has an online portfolio (especially flickr) that may say what camera/lens he uses etc in the metadata, or just show what subjects he likes if you don't want to ask!)

Your best option however might be a book; understanding exposure and the photographers eye are ones often mentioned here that are pretty universal to any model camera or photography subject. (I don't own exposure, but I believe it's pretty useful for most beginner to intermediate shooters, Eye is probably a little more intermediate+ (it's understandable to all levels, but you have to want to put the effort in to use it if you see what I mean!))

You should try 'The Photographer's Eye' by Michael Freeman.
http://www.amazon.co.uk/The-Photographers-Eye-Composition-Photographs/dp/1905814046

The Olympus 25mm (if that's what you have) is really, really great. I spent a year shooting almost exclusively with that for a 365 project, and came to love it (just wish they made a 17mm of the same quality).

There are two books I always recommend to anyone just starting out, as they really helped me: Understanding Exposure and The Photographer's Eye. Might be worth a look!