Like fvike mentioned there are one piece gaskets for the older pain with ribs on the gasket rails and for the newer pans with smooth gasket rails. Make certain you have the correct gasket. I've had good luck with Fel-Pro's Perma Dry Plus one piece gaskets. But it still takes a fairly heavy film of silicone on both sides of the gasket around the rear main cap and timing cover, and a dab of it in the corners. I leave the gasket on the side rails dry.
Also, the Fel-Pro Perma Dry Plus oil pan gaskets come with four plastic retainer studs that thread into the oil pan bolt holes and hold the gasket in place. Push the oil pan up and they also hold the oil pan in place. Get a few bolts starts then simply unscrew the plastic retainers. They help a lot.