Different artist may make such scene in different styles and ways. However, I am now presenting my own basic work-flow to achieve that natural look. My working platform is 3dsmax7. But lower/upper versions should not make problems for following these techniques.

This is a basic tutorial. So, you may need to play with your own ideas and techniques (simple to medium) that you have for achieving more natural looking after you get the idea from this tutorial. That is up to you.

This is for newcomers in Max.