I usually roll through Stop signs after looking in ALL directions, if there are no other cars. Otherwise I will slow down until at least the other cars have gone. If there are multiple cars then I will stop and go on my turn just like a car.

Stop lights I stop, then go through if it's clear. The law here says that bikes must come to a complete stop at a red light, but may proceed if clear, due to bikes not triggering the sensor loops and such.