There is no magical secret to gaining more distance off the tee, but there are some general rules of thumb to keep in mind that affect distance overall. Have you ever noticed that the harder you try to swing the club and the further you try to hit the ball, the worse the results? That is because distance (as well as direction) is determined more by where the ball comes into contact with the clubface at impact than how fast that clubface is actually traveling.
If you have a very high swing speed but the ball is not hitting in the center of the clubface you certainly will not see the distance you are looking for. To increase your distance off the tee, work on developing consistency in your golf swing so the ball hits the center of the clubface at impact every time. You accomplish this by relaxing your arms and hands, and thinking about "swinging the club" instead of trying to "hit" the ball. The more relaxed you are, the better the results. Many of my students have found much more distance off the tee when they slowed down their swing because contact was much better.
You might also find a bit more distance off the tee by teeing your ball slightly higher and placing it about a half inch further up in your stance. This makes it a little easier to get the ball in the air and many times you will find it carries more. But this is not a replacement for working on the consistency in your golf swing.