1. Matt’s comments deserve repeating. But just remember, you do want the clutch out, and some power going to the wheels as you make your turn. He goes on to describe this as just enough gas to maintain speed. Actually, you want to be accelerating (slightly) through the turn. (It’s partially a semantic thing–you need to be accelerating to ultimately maintain consistent speed and properly load the suspension.)
2. Don’t, don’t, don’t downshift and then wait for the turn to let out on the clutch. Need for accelerating through the turn aside, of all the places to be surprised that you’re in the wrong gear for your speed, finding out mid-turn is one of the worst.
3. Downshifting is debated with cars because, by some accounts, the wear on the clutch may be ultimately more costly than the wear on the breaks. You don’t have the same question/issue on your bike; it can take the downshifting just fine.
I was surprised in my MSF course that they didn’t teach blipping the throttle up to match RPM’s in the downshifting process. Personally, I think it helps with smoother downshifts.