And you may want to use a Net Suit instead, which is as it sounds, and rolls up smaller than an NBC suit.
Use a glue pen to fix the Hessian on. Rough it up with a wire brush, so it looks less like bits of sack and more like fibres.
You can dye the Hessian first in various colours, depending on where you want to use it.
You can also add strips of green elastic, in strategic places, so you can add bits of the natural undergrowth, for the ultimate effect. Just consider what position they will need to be in.
Don't forget to camouflage the soles of your boots. That is a mistake, several Snipers have not lived to regret.