A good tool to help you judge distance and speed is to toss a golf ball toward the hole before putting. This allows your mind to know how far away the hole is.
After you have thrown the ball, immediately begin your putting practice strokes. Move the putter back and forth to get a feel for the distance.
After following this routine, setup to the ball and execute the putt. You will be amazed how much this drill improves your distance putts.