It's pretty easy if you are a generally confident driver. The driving style is very relaxed outside of major cities (and even they are rarely anything worse than a town centre in the UK). In my experience people will move off slowly, skip the lights a bit, not get angry, let you out if you are waiting and most drive within 10 MPH of the speed limit (above or below).
The only thing worth checking is whether there are any particular rules for that state. When driving in Michigan, for example, you need to be aware of the 'Michigan Left', as it's known. It's quite logical, but knowing in advance helps! Especially as you can sometimes turn left on red in Michigan, like in many other US states (in addition to the common right turn on red).
EDIT: One other thing. Unless you are in California, stop at stop signs. In CA you can get away with a rolling stop, but anywhere else they will enjoy writing you a ticket!
EDIT2: Traffic lights. Flashing red lights means it is acting as a stop sign i.e. stop, proceed with caution. Flashing amber means proceed with caution, but no need to stop. At quiet times you might find an intersection between a major and a minor road, with the major road having flashing amber and the minor road flashing red. It's basically be aware that people from the minor road may be pulling out, and for the minor road it's basically stop and give way to traffic on the major road.