Taping, moleskin, baby powder, and Underware gloves work very well for me.
Get Johnson & Johnson adhesive tape in both the 1/2" and 1" widths. Cut some moleskin to cover the blister area at the base of your fingers - approx. a 1 1/2" x 3/4" square works for me. Next, extend your fingers so that the skin on your palm is taut. Then take the 1/2" inch tape and cut a ~5" length. Wrap this around the back of your finger at the base and form an "X" with the tape across the moleskin on the palm of your hand. I do this for both the ring and middle finger on both hands.
Next take the 1" tape, and - starting on the back of your hand - wrap the tape around your hand, taking care to snug the tape on your palm. I wrap three times around my hand, finishing on the back of my hand. Once you've done this, clench and unclench your fist, noting where the tape feels restrictive. Then take a pair of scissors and cut slits in these restrictive areas.
I also use the Pro-Grip superbike grips, as they're a little larger diameter-wise than normal grips. This helps keep me from closing my hand so far around the grip and holding on so tight.
Yes, it's kind of a rigamarole, but your blister problems will be gone.