Let your palm be the pilot
Set your putter behind the ball and position the grip in your right palm before placing your left hand on the club. The grip should be in line with your forearm (right), and the putter should feel like an extension of your arm. Avoid the fault of gripping the putter in your right fingers (right inset).
Put the push on
Your right palm is now facing the target, which is where you want it at impact. Your through-stroke should feel like you're pushing the ball down the target line with your palm.
This stroke will point the clubface to the hole as you follow through (right). You'll release the clubhead for a more consistent roll.
Drill Instructor - Flag down short missesA typical flagstick is 7 feet high. Lay the stick down 1 foot from the hole, and drop three balls at the flag end to mark 8-foot putts. Place a few more balls 2 feet closer (for 6-foot putts) and finally some more 2 feet closer still.
Start with the shortest ones, and work your way back until you make nine in a row. When you need to make putts of this length on the course you'll know how.