as several people have mentioned the position you shoot in and how mobile you are will determine just how elaborate of a ghillie you build. I shoot a rifle right handed to the right shoulder area is clear allowing for proper positioning and cheek weld. most ghillies have a canvas front for durability while low crawling, padded canvas elbows for comfort and durability and then a netting on the back to start. you can add as much or as little jute or burlap as you want to the netting. after you are finished you will want to do a "ghillie wash" traditionally you wear it and roll around in a mucky pond to give it a natural smell and get rid of any bright colors, if you want to stand on the bank and dip it in by hand you could do that too.
here is applying the canvas to the front of your suit.
here I applied the netting to the pants and top, also you might want to cut out a middle section and then sew in a fine mesh to help keep cool, keep the shirt together, and bugs out!
id post a pic of my finished product but I cant find one so if you want I can take it outside and take a pic for you.