Wishing for the stars to come out

Hello and welcome! I'm assuming if you're reading this, it is because you want to learn to make photorealistic elevations. This tutorial is written for CS3 since that is what I run on my personal computer, but it will definitely work with any CS version of photoshop, and probably most other versions. The screenshots may not match perfectly but it shouldn't be too hard to decipher. This tutorial may not be compatible with any other image editing program! Photoshop has unique tools that may or may not be available in other programs. Unfortunately, I don't use any other programs so I can't provide support for them.

I have tried to make this tutorial as comprehensive as possible. Some people will probably find it too dumbed down, and others will find it difficult. I have attempted to find a middle ground. If I have left something out or any steps are too confusing, please let me know! I will include a "troubleshooting" section at the end of each tutorial to include anything I think might go wrong. Any questions I receive will also go here.

Difficulty: medium
Tools Needed:
-Photoshop (obviously)
-Mouse with scroll wheel (photoshop is extremely difficult to use without a mouse or tablet)
-Internet access (for texture references)
-High-quality line drawing elevation image

This tutorial will NOT cover how to obtain Photoshop, where to find texture references/how to edit textures, or where/how to get an elevation. Those issues may or may not be addressed in another tutorial. This tutorial is not for beginners! It is assumed that you know the basic Photshop tools and how to use them.
All that being said, ( on to the tutorial... )