Yield on entry
Vehicles already in the roundabout have the right of way. Slow down on approach, look left for traffic in the circle, and enter when there is a safe gap. Never stop in the circle once you are in it; pause only at the entrance.
Stay in your lane
Multi-lane roundabouts have lane markings at the entry that tell you which lane to use for which exit. The right lane is usually for the first exit and right turns; the left lane is usually for the later exits and U-turns. Pick the correct lane before entering.
Signal at exit
Signal your right turn as you pass the exit before yours. This tells drivers waiting to enter that you are leaving and the gap is clear for them. Failure to signal at exit is one of the most cited issues on road tests in roundabout-heavy areas.
Emergency vehicles
If an emergency vehicle approaches while you are in a roundabout, exit at the next exit and pull over once clear of the circle. Do not stop inside the roundabout.