Another important aspect is to not bob your head. Some swimmers lift their head to breathe and then drop it back down during the recovery. You want to maintain all your momentum in a forward direction and lifting your head destroys some of this momentum.
Check out this slow-mo footage of Rebecca Soni's stroke as an example:
3ToRgDSzh34
She does lift her head a little, but she always keeps her chin tucked and her eyes looking toward the water rather than at the far end of the pool.
One tip I've heard is to fix your eyes at the position your hands are at when you begin the pull and that's where you should keep your head.
Another important aspect is to not bob your head. Some swimmers lift their head to breathe and then drop it back down during the recovery. You want to maintain all your momentum in a forward direction and lifting your head destroys some of this momentum.
Check out this slow-mo footage of Rebecca Soni's stroke as an example:
3ToRgDSzh34
She does lift her head a little, but she always keeps her chin tucked and her eyes looking toward the water rather than at the far end of the pool.
One tip I've heard is to fix your eyes at the position your hands are at when you begin the pull and that's where you should keep your head.