The arms are the key to a fast front crawl, so you have to learn how to make the most of every stroke.
The first step in the intermediate phase is improving your head position.
Try to direct your eyes towards the bottom of the pool in the direction in which you are travelling, similar to the way headlights point on a car.
Let your shoulders and hips roll slightly, but stay more on your front than your side. This will help you be more streamlined in the water.
Stretch your arm forwards at the start of the stroke and let your shoulders and hips follow.
Keep your legs close together and use the long, shallow kick described in basic front crawl.
Imagine being able to feel your big toes touching each other as they kick.
Your arms provide the power. Use the alternating action, bending your elbow and pushing your hand towards your feet.
After you have put your hand in the water and stretched, try moving it slightly out and then pulling it down below your shoulder and elbow.
Now press your hand towards your feet with your fingers following a path down the middle of your chest and stomach.
Try improving your recovery - the part of the stroke when you return your hand to the start position - by lifting your elbow out of the water first, as if you are trying to push it up to the roof of the swimming pool.
Keep your hand near the water and close to your body as you move it back to the start position.