Rain can be very dangerous, but not always. Car tires tend to keep the road clean where they travel, but the center of each lane tends to accumulate various oils. Few things on this planet are as slick as wet oil. Once it has been raining for half an hour or so, the water washes off all the oils and you are left with just a wet road. You do have less traction, but it's not too bad. You still have about 90% of dry traction even on a wet road. Motorcycle tires are good at cutting through water because of how they are shaped. They work kinda like how a submarine cuts through water. (If you ride on the dark side, all bets are off.) Just don't try to scrape pegs or anything like that. You'll get in trouble pushing things in the rain.
That center stripe is slick as snot in the rain no matter how long it's been raining. Avoid that like the plague! In fact, anything that isn't concrete or asphalt is going to be slick. Be careful with bridge expansion joints, manhole covers, temporary road repairs, tar snakes, and anything that doesn't quite match the rest of the road. Discoloration means something is different. If something is different, traction is going to be different too. Watch out! Also remember that the road is wet, so it will be harder to see gravel or other road debris. Take it easy and you'll be okay.
Intersections can be particularly bad for accumulating oils, so use extra caution there. A few drops of oil or coolant at an intersection can result in a really bad day. On wet roads, that drop won't stay where it falls. It can easily end up in your path and get a slide started. Keep a little distance between yourself and the car ahead of you. It will increase your chances of seeing an oil slick.
Just like in a car, light throttle and brake inputs are your friend. Throttle because you don't want to burnout. Brake because your disks will be wet. They have to be dry to work well, so they might not bite like you are used to at first. If you have a rain mode, use it. Don't try to be tough guy or too cool for fancy rider aids. It isn't worth it.
I'd suggest going the same speed as the traffic around you, but be extra careful to not be in a blind spot. Visibility is low for you and for them. You are small and easy to miss. Don't let traffic box you in. Always have a good escape route. If you are slower than traffic, you run the risk of someone coming up on you and not realizing that you are a small bike and not a car farther ahead. If you are faster, well, you're probably going too fast for road conditions. You could also be blinded by the spray behind a vehicle and not realize that they are going much slower than you expected. Just try to blend in but be visible.
And the most important thing: Relax! Nothing is worse than a death grip on the controls. It will make the bike unsteady and it will be physically and mentally draining on you. That's a recipe for disaster. Loose grip on the controls, not much weight on your hands, etc. You know what you are doing. Trust yourself and your bike and relax.