Have an order of operations. Jackal snipers need to be taken out asap, so use a carbine or a sniper weapon for those, then if you like you can usually jump into the fray with a Plasma Pistol and automag/carbine. Be sure to take out as many of the grunts are you can so they don't shoot you as you're releasing the overcharges you'll use to EMP the brutes. Use the PP for the brutes, and headshot.