nowadays i use the BT digicam stuff (can't remember exactly what pattern type it is) but i always got the best results using good old DPM (97 i think). The amount of times, without a ghillie suit or anything, i'd be lying in a bush less than 10 feet from people walking down a track and no-one spotting me was awesome. But as has been said before, a huge amount of it is in positioning yourself where you'll break up your outline, and having the discipline to stay still and not pull the trigger until you have to/need to. I've completed so many scenario missions, circumnavigating the whole map, without firing a shot, just by clever and careful positioning to allow people to pass by before i carry on.