Small bead of "the right stuff" layed around the inside of the rubber gaskets and covers will stop most leaks.
Also put short beads along the edge of the front cam caps where they meet the head. (The inside 90 corners, there are 4 of them.) This is a common leak point. You should have layed 4 short beads of this stuff there when you put the front caps on too.... If not, pull the caps, clean up everything, and then put down the beads. If your careful, you might not need to pull the timing cover, sprokets etc. (Don't smash the cam seals or you'll have a leak there after you solve your cam cover leaks.)
Did a great job on one motor, and then was almost out of the "right stuff" on this one, and it's leaking now.. DAMN. Should have bought another can of sealant, but now I get to do it again.. (Sound familliar?)