You are the quarterback of your vehicle, so it might help to know when it's acceptable to attempt a pass. 

When you need to pass a vehicle in front of you, either because they're traveling too slowly or because you can't stand to look at all those bumper stickers for another two seconds, make sure you have enough room up ahead in which to perform the maneuver. 

Unless you absolutely have to, don't try passing another car on a two-lane road. Too many bad things can happen unnecessarily. Have patience if you can, especially when preparing to pass bicyclists, as they're obviously more vulnerable. Haven't we gone over bicyclists already? Pay attention.

If it's safe to do so, signal and begin to pass the car in front of you. You'll need about a 10 to 12 second gap if traveling on a highway at around 50mph. If moving faster than that, you should obviously allow yourself a larger gap.