Attacking from the sides is the best way to farm mechs. This way the Center Torso doesn’t get damaged a lot lessening the chance that you’ll accidentally kill your target mech. This also in turn focuses the damage to the Leg and Arms/Side Torso which contributes to pilot injury, especially noticable with Precision Shot.
Always check how much Structure and Armor is remaining on the part that you are targeting by looking at the paper doll. Using excessive weaponry might kill the target through damage transference. If possible only use weapons with high amount of stability damage. Turn off your Lasers.
-Flank a side of the enemy, do not target the front.
-Focus fire LRMs until it gets knocked down. (+1 Injury)
-While knocked down, use called shot to focus fire on one Side Torso. (+1 Injury)
-Reserve until the Target Stands up.
-Use Precision shot on leg until he gets knocked down again, preferably target the leg the same side a Side Torso is still intact. (Destroying a leg guarantees a knock down). (+1 Injury)
-While knocked down again, use called shot to destroy another Side Torso. (+1 Injury)
In the highly unlikely event that the Pilot is still not incapacitated with 2 Side Torsos destroyed and 1 Leg destroyed, the best option is to destroy the other leg, which should at least give you 2 Salvage instead of 3. If their rear armor is still intact, you can still go for one last knockdown.
Sometimes enemy pilots have less than 4 guts and will only need 3 injuries or you will get a lucky Head Hit thus making it easier to incapacitate the pilot.