Thats a great little explaination from Lorri, thanks Trek for pasting it here.
I wish I had read something like that when I first began... alot of it is about confidence... the fastest I go down windy hills is about 35km/hour (about 20 miles?) but on a long straight flat I have gone over 60 km (about 38 miles?).

I don't like to go down fast on hills and when out riding with others, if I manage to keep up with them going up the hill, I inevitably get dropped going down the other side.

One thing to add to what Trek has posted and that is to reinforce the looking where you want to go... not where you want to miss.
Recent research of motorbike crashes showed that they were often with telephone/power poles, or some other object that has heaps of space either side. Why were these bikes crashing into the only thing in metres and metres of space?
The researchers found that the bikers would see, for example, a power pole on a corner, and be watching it to make sure they didn't hit it, but by focusing on it, they ended up taking a line straight into it.
So notice the hazards on the rodside, but don't focus on them... focus on the clear bits of road - not the pile of rubbish or stones on it; focus on the line you will take around the corner - not the tree you want to avoid; focus on the road a metre out from a parked car - not the door that might open as you pass...

Good luck with your increasing confidence, it happens with time and as your bike becomes more and more a part of you.