PhotoshopCAFE has a couple dozen tutorials on creating various kinds of special effects in Photoshop. The effects include drop shadows and photographic edges to realistic reflections and built-from-scratch rope coils.
Each tutorial is broken down into small, novice-friendly steps to help beginners (and even intermediate users) learn some Photoshop fundamentals. Some also include a PSD file which you can download to see the effect firsthand.
Once you've mastered them, check here for even more.