Contrary to the above the most important thing for rain riding is to stay warm and dry. Being comfortable allows your brain to work properly because it has no distractions trying to keep you comfortable. Good gear is step one.
Ride normally while being aware of reduced braking. Modern tires have more grip than most riders will use in the wet. As the age/wear that diminishes so keep that in mind. Do your best to avoid heavy traffic even if it means a longer ride. Unless absolutely necessary avoid abrupt actions. Concentrate on being as smooth as possible.
The important part is practice. Yep go ride in the rain and gently seek the limit of maximum braking. Don't do this on a crowded highway. Find an empty parking lot and practice braking harder until either you become very uncomfortable or find the edge,always being ready for that sudden loss of traction. Don't do this in standing water. A sure way to find the value of your gear.
Once you have the braking down try cornering in the wet. Using the same empty parking lot ride in BIG circles and gently seek the edge. Keep the smooth riding in mind and increase speeds until comfort becomes slim or you find the edge.
Been riding for 50 years on/off road and still screw around with this. And I love a good mud race off road. If you can buy a dirt bike and ride off road. It's the best way to learn control of a motorcycle in adverse conditions.
Have fun and approach it without apprehension. Pay attention to what the bike does and what you do to control it when things get dicey. learn to ride well and you'll ride for a long time.
If you're going to be crazy,you have to get paid for it or you'll get locked up.
Hunter S. Thompson