Sand the non-fiberglassed surfaces of the exterior hull lightly with 120-grit sandpaper.    If you intend to varnish the exterior, you should switch to 220-grit for a final pass.    Roll on a coat of epoxy.   This coat will begin to "fill the weave" on the external fiberglass, and will be the first coat on the topsides of the hull and undersides of the rails.