smear the gasket with grease
I second this
I make sure both mating surfaces are totally cleaned of old gasket material, and any previous sealants. Coat both sides of new gasket (I use Best Co.) with grease, and install gasket and intake. Then torque to spec., and re-torque a couple times after heat cycle.
Re-torque the intake manifold? I've never done that, only head gaskets.