The one technique ,more than any other, that helps me to hit the ball with more consistency and pace is keeping my eye on the ball. We have heard this a thousand time but few of us really go to great lengths to perfect it. What I personaly do that helps me is to actually focus on the bounce just prior to making contact with the ball. This sets up a rythym to my shot making but more importantly is ensures that I make accurate and repeatable contact with the ball.
However the problem for me is to the same thing during my matches. Under the extra pressure of a match it becomes harder and harder to practice what I preach.