Do you mean in places where you've had to take the lane and there are no bike lanes?
I try to bike along routes that have a bike lane, but on occasional stretches I ride in the right-hand traffic lane. I wouldn't want to do this for any extended period of time in a stretch that is heavily trafficked, but the best tactic seems to be to ride in the middle of the lane so that cars need to properly pass you (not barely brush past you, while trying to stay in the same lane that you are occupying). You should also make sure that you are *very* visible.
+this. I like to think of it as being assertive - not aggressive, but stand up for your #@*ing rights and space.
(a) If there's no good shoulder, take the WHOLE lane, and make sure the cars know it.
(b) Front and rear blinkers, day and night. I'm a big fan of:
(b.1) Cygolite Micro rear red blinker;
(b.2) Cygolite Dash 320 (or thereabouts) front.
The dash has a "daytime flasher" mode that's ruthlessly bright. I've noticed a pretty marked decrease in cars trying to turn right into my lane since I started using it. Not 100% -- drivers are still idiots -- but it helps make you really obvious.
(c) Go fast. The closer you are to the speed of the rest of traffic, the better.
(d) You didn't mention the speed limit on the roads you're talking about. If it's > 40mph and not somewhere in the middle of nowhere, I start to think it's time to find a new route. I'll ride on 50 or 55mph roads to get somewhere, but it's stressful, and not something I'd want as part of my daily commute. A 35mph road, on the other hand, if you're at 20 or 25mph, isn't too bad.