Here you can acess leveldesign tutorials I have made. I currently only have a fiew but am trying to cover many specific topics that I feel need to be more thourghly explained. The tutorials range from beginner-intermediate-advanced.

Beginner tutorials will require no prior knowledge of external programs just a decent understanding of GtkRadiant.

Intermediate tutorials will require a relativly good understanding of Gtk and some external programs like Photoshop.

Advanced tutorials assume that you know GtkRadiant and Photoshop pretty well and have a good grasp of the game engines structure.

If a tutorial is not a link, then it is not complete yet.

Basics of a shader explained
What to avoid
Custom compile codes

Creating Holographic panels
advanced brush minipulation
VIS process

Alphagen function shaders
Creating terrain in GtkRadiant
DotProduct texture blending