When blowing shit up, it sometimes helps to click on the structure, then click away as soon as it flashes. Helps the little bugger to avoid some of the shrapnel. It does require a little bit of luck, but you shouldn't be having huge amounts of trouble with it...
Don't take on vehicles. Follow them but never get close enough for anything to see you. You can spend a good amount of time surveying everything before doing anything too drastic, thanks to the huge sight radius. You can kill any of the soldiers without too much fuss being made in most cases. Just make sure you get the first shot in.
Eventually you'll want to sneak into the base from the west side and the structure you're looking for is pretty much on the east side - once you're in the base, you just need to gun it. You'll have everybody after you but as long as you make it to the structure before being killed you'll pass.
Don't take on vehicles. Follow them but never get close enough for anything to see you. You can spend a good amount of time surveying everything before doing anything too drastic, thanks to the huge sight radius. You can kill any of the soldiers without too much fuss being made in most cases. Just make sure you get the first shot in.
Eventually you'll want to sneak into the base from the west side and the structure you're looking for is pretty much on the east side - once you're in the base, you just need to gun it. You'll have everybody after you but as long as you make it to the structure before being killed you'll pass.