In Farcry 2, just before you assault a base:
1.
Look at which way the grass is swaying. This tells you the wind direction.
Find a barrel at the edge of the base or in it, that will set fire to nearby grass.
Make sure the wind will sweep the fire into the base.
Use a barrel, a molotov or two, a flare pistol or a flamethrower to set it alight.
I prefer to snipe a propane tank or two. When they are shot, they fly around spraying fire everywhere. Very good for lighting up a large area in one hit.
2.
BACK THE FUCK UP.
Get back to your sniper position and pick off the fools as they run from your fiery assault. Use a sniper with a clip.
Another thing I do, is find a nice big hill overlooking a base. I sit on it and fire a rocket at the end of the base furthest from me. This will cause the fools in the base to run away from the fire, towards you.
Shoot them in the fucking head with your sniper rifle repeatedly.
I use the rocket in areas of dense jungle, cos you can't burn anything in there, dammit.