Ditto Bigger Al: smooth, smooth, smooth. Work up to the limits gradually and feel where they are braking, cornering and exiting on the gas. I'd focus on braking and exiting first as they are the easiest to recover and adapt as traction goes away. Generally, there's little chance of catching and correcting a slide when healed over mid corner in the rain. You might be lucky and catch it on your knee and save it, but . . . .
One of my greatest racing spectating memories is of the 883 class at Road Atlanta in the early '90's. Pouring down rain. Everyone had clipons and was tippy toeing around the track. I was watching at Turn 3, the big left hand sweeper atop the esses (before they eliminated it and put in the current abortion). Ben Bostrom had removed his clipons and put on a handlebar. He'd come thru T3 WFO, fully crossed up, foot down and a huge rooster tail coming off the rear tire, both ends sliding as he "dirt tracked" his way around Road A. A great show and a great memory.
You say you have "suitable tires" for the rain. Are they race rains, or something else? Race rains are amazing tires and you can achieve a lot more than you might suspect on them. If you have DOT's that have siping, or an aggressive tread, they are NOT race rains, and they will not have the traction of race rains. Race rains are also compound and construction, not just tread pattern. I've used soft compound dirt track tires and low pressures with some success in a pinch, but again, they ain't rains.
I hate racing in the rain. To me it is a bit of an oxymoron, but then I don't live in the UK where it rains more than not. Good rain racers are, to me, amazing. Their balance, feel, control, and concentration are a wonderous combination. Good luck.