Riding in the wet

[Grahamm]

There's some excellent advice above which pretty much covers everything, so the only thing I'll add is to invest in some NikWax Visor Spray because it's great for stopping rain and spray from screwing up your view and a Pinlock or Fog City insert (or a breath deflector) to stop your visor misting up on the inside.

And always remember to be able to stop in the distance you can see is clear, so slow down and give yourself extra space for braking distance.