Footwork is a must in tennis. If you can't get to the ball, you can't hit. All the fancy strokes you've learnt won't help you at all.
It helps to be on balance. Mis-hitting balls, or even completely missing, is often caused by a lack of balance as you are not set up in a comfortable position.
Your skills will improve rapidly when you can make contact while balanced, both feet grounded, knees slightly bent and keep your head still. Good footwork helps you achieve these balanced positions.
Between shots keep on your toes, don't stand around flat-footed. All good players use the bounce step to keep poised and ready to spring into action.
The message gets from your head to your feet faster if you get on the balls of your feet, flex your knees a little, and bounce rhythmically between shots.
Shuffle step to the ball. Many small steps are better than a couple of long steps. This also helps you time the ball better. If the ball is wide and far away for you that's when you have to pick up your feet and run! Taking a number of shuffle steps to the ball makes it easier to make an adjustment and be on balance.
When the ball is wide you must run towards the ball, don't make the mistake that many players do of moving sideways to hit a ball. Run forward to the ball, shuffle, step and then hit.
Don't turn your back on your opponent when returning to the centre of the court. Your opponent may hit the ball behind you. Slide-step back into position after making the play, keep your shoulders and feet parallel to your opponent.
If you find yourself way out of court after hitting the ball just run back as fast as you can, as the sidestep can't help you then.