TURN THE CORNER: Set up well in advance of a curve and do whatever braking needs to be done before entering the turn. If you are riding in a group, move away from the others. This will allow you to take your preferred line through the corners, which is critical because you may not have time to adjust once you commit. It also allows a greater margin for slowing.
BRAKE IT DOWN: For long descents, use both brakes equally. Remember that once you're in a turn, any traction used for shaving speed significantly reduces the traction available for cornering. In wet conditions, it will take you longer to stop. Lightly apply the brakes periodically on a wet descent to remove excess water from the rims.
BE READY: Don't compete on descents with anyone other than yourself. That's because on any unfamiliar road, caution is paramount: You should always be prepared for road debris or traffic around every blind corner.
EASE UP: The most important aspect of descending is relaxation. Anxiety can narrow your concentration, which could cause you to miss a hazard in the road ahead. And the best way to be relaxed is by practicing descending as often as possible.
I will add: Stay within your comfort zone! Not worth it to go out of control. But the more you practice, the more you will be able to push the comfort zone.
This is from bicycling.com.