Wear as little as you can -- it keeps the sweat down.

Wear thin wool socks -- they don't hold as much water.

Ditto thin gloves and chamois -- they're yucky when they go "squish."

Fenders keep crud off you and your bike. Put some on if you're going to make a habit of riding in the rain.

Keep going until you're done -- it always drops 20 degrees when you stop.

Oil the chain as soon as it dries. Wipe the bike down when you get home.