Introduction

So what IS a Ghillie suit?
A Ghillie suit is a heavily camouflaged suit that is designed to mimic heavy foliage, and also to break up the outline of the person wearing it. It is used by snipers across the world and also by civilian for hunting or paintballing/airsoft.
A Ghillie suit is different from a Bush Rag or a Yeti suit. The main difference is that a Ghillie suit keeps the front of the suit free from camouflage (except the pattern of the flight suit/BDU's underneath). This is done so that the user is able to crawl across the ground without tearing the camouflage off their suit. A Bush Rag has camouflage on both the front and the back and is used mainly for stalking in the crouched or standing position.
And last but not least the Yeti suit is simply a regular flight suit or BDU's (battle dress uniform) that has natural vegetation attacked to it (via rope or string). All of these different suits are highly effective but only when employed in the correct  circumstance, (e.g. you wouldn't crawl in a Bush Rag but you wouldn't stalk crouched in a Ghillie Suit)
Here are a few pictures to help illustrate the difference:

Here these two snipers are using Ghillie Suits, as you can see the camouflage is on their backs only leaving them free to crawl.

Here the guy is wearing a Bush Rag, his whole body is covered in camouflaged material

This is a Yeti suit and as you can see the natural vegetation is stuck to him, instead of being part of the suit. (sorry this was the best picture I could find of a Yeti suit, you can imagine the results I got off Google when searching for a picture -.-  )

So now we know the difference lets begin making a Ghillie suit!