Keeping the gasket lined up to the bolt holes while you put the pan back in its place is easy as raping the willing. Throw a SMIDGE of assembly lube on the bottom of the gasket so when you lay it on top of the pan it wont move when you try to align the holes up for the bolts. cake.
Sealer is a good idea but i never ran into problems with leaks after changing it. I might have been one of the lucky ones.