I'm car free, so I use my MTB bike and public transit for just about everything.
Salem, OR is a pretty bike friendly city, so I have the option of sticking to bike lanes or back roads most of the time. There are a few busy spots where I'm a regular part of traffic that aren't so bike friendly and I ride in the middle of the right lane because I don't want to get run off the road when someone thinks they can squeeze between me and the car in the left lane. It also keeps me out of reach of sewer grates, potholes that always seem to be right next to the curb, blind right-hand turners, and the ever dreadful driver's side doors.
I tend to right through red lights if its safe and I don't stop at stop signs unless there are cars coming, other than that I follow most of the rules. You know, stay in your lane, obey the speed limit, blinkers...
Oh, and I'm a huge advocate for flashy things. Red lights, blinky lights, reflectors, refractors, flags, led wire, flare guns, anything so you're visible in the dark.