I stick around my zone and, if nothing shows up for a while, adjacent grids. If a convoy or task force pops up nearby I'll go after it (if it's less than 7-8 hours travel to intercept it) before returning to my grid. Usually I'll use most of my VIIB's torps in one or two runs against a convoy though, so often I'll just set course for home after that.
If nothing at all shows up for a week or three, on the way home I'll drop by somewhere I can expect ships. Wouldn't want the men to come home empty handed.
