This is one of the most comprehensive workflow Tutorials for Landscapes in blender.  He talks about how to blend textures, use meshes instead of displacement, and using lattice for randomness.   If you watch this video 3 times, first take the info in.  Second, take notes, third, Try different parts using his Add on. (free version)

The secrets of luminaria contest.

This was made with ai not blender. Davinic to edit. and music maker for the music.

3d total has quite a large free section of magazines and information relating to 3d.

You can get the free stuff here.