I really can't seem to get the hang of the stealth in this game. It just seems impossible to me.
I look at an outpost from every imaginable angle, and tag all the enemies, then try and work out which order to sneak up on them from, but as soon as i take out the first one, i'm spotted, or someone discoveres the body etc,
I was eyeing up an outpost the other day, trying to work out a strategy, when two carloads of blue guys turn up and start a gunfight. 5 mins later, i take out the one remaining enemy with a sniper and BOOM, outpost cleared without being seen. Awesome.
That, and the one time a tiger did it all for me are the only times i've done it without being seen. All the others i somehow trip the alarm and then find a nook to hide in and pick them off as they come to try and find me.