Get to know Photoshop as best you can I think. Martin Evening has great books on PS “Adobe photoshop for photographers cs3”, I would recommend these. Also find, read and do as many of the online tutorials as you can.
On a personal note I am not a fan of 1x.com/onexposure.com. I used to like the site but find that the pictures are just to technically perfect. 1x for me anyhow is a step to far. Pictures on 1x are starting to move from being photographs to being digital art. There are still some honest photographs being accepted but these are being accepted less nowadays. For that reason I don’t really look at 1x anymore. Absolutely nothing wrong with 1x if digital art is what your after but for me its not photography, i’m sure other will disagree though:-)
Sorry for getting side tracked, Martin Evenings book is very good I am sure some of the others here will have some other suggestions also for books, best of luck