What do you guys do for patrols??

So Im in a bit of a bind and need some guidance, more like Id like to see how you individual Kaulens do your own war patrols. Usually Im givin a sector (in this case BE29, the only reason I waste fuel is because Im still playing at very low realism and once I get the hang of things more my first 'changes' are going to be limited fuel, air and etc and probably duds, pretty much everything except manual targeting) to patrol and I do go patrol it, however I make it a habit to pass some 'areas of opportunity' along the way like on this patrol I went up and around England around the top of Scapa Flow and managed to find 2 merchants on the way, my new plan is to sit on the edge of BE and AL and patrol back and forth in about a 100-200 km line (3 convoy lanes converge here) and wait until something nice pops up. if nothing comes up for a few days I plan on heading back to base but trying to maybe sit outside of scapa flow for a day and maybe pick up a nice merchant contact or two (this is where my last two sinkings occured)

But my question is, what do you all tend to do on patrols?? Id really like to find some 'nice waters' that any of you could reccomend, yes the shipping lanes map helps but theres got to be some stuff thats not represented on it right??

PS: many say its not a good idea to go through the Dover Strasse(Strait)? When should I stop using it? I havent yet but Im in 1939 and figure around 40 I should not use it at all then.