Tutorial by Mark Crilley: How to Draw Backgrounds (3 Point perspective)

There is a trick to it which will make your action scenes look deeper, with more thought to the page. If you master this, you can give any of your frames a lot of life.

Tutorial by Mark Crilley: Backgrounds - One Point Perspective

So far one of the best I've found. There is no definite way to do it, but it has the best explanation. I love how it showcases the different effects and types you can achieve for your story :)