Ride in the tire tracks of the car in front of you.. If you are by yourself, with no traffic around, then ride closer to the lane markers.. Cars indent the asphalt in the usual riding positions, so if there are no vehicles around you, ride closer to the lane markers, where water doesnt collect.
Also, because motorcycles have thinner, rounder tires than cars, it is harder to hydroplane a motorcycle, but there is no recovering from a hydroplane like a car either.. take it a little slower, and smooth on the throttle.
One more thing.. depending on where you live, some roads are Asphalt, and some are concrete. Concrete is MUCH MUCH more slippery than Asphalt in the rain, so be EXTRA careful on Concrete.