[mike p]

Following is a technique that was taught to me when I started freediving and I still find it effective today:
1. Adjust your buoyancy so you are positively buoyant from the surface down to fifteen feet.
2. Lie face down in the water and breathe through your snorkel until relaxed.
3. Slowly inhale until your lungs are so full that taking in any more air is impossible.
4. Hold that breath for a few seconds.
5. Exhale slowly until you have completely emptied your lungs.
6. Hold that breath for a few seconds.
7. Repeat this process a few times; you are not trying to hyperventilate so keep the process slow.
8. As you inhale, drop your upper body downwards while lifting your feet and legs (their weight will drive you downward) and give two slow kicks to get below fifteen feet. Maintaining your calm, swim gently using only your feet. The amount of oxygen used for underwater sprints is not worth the time saved in reaching the surface...you have more oxygen in your system than you think but the supply is far from inexhaustible.
9. The use of good freediving fins and a good low volume mask help quite a bit.

Dive well and with care. Mike P