I am privileged to dive with new divers almost every week, lately. The above advise I stole for NWGD many moons ago, and when applied, works every time.NWGratefulDiver:Here's my suggestion ... try these things first, then once you've got the technique, work on shedding some of that lead.
When you're ready to descend, as you raise your BCD inflator hose take a big deep breath in. Don't start to breathe out until you start to sink to about eye level. Then start a looooong, deep exhale ... take about five or six seconds to let all the air out of your lungs. Then, just when you've finished exhaling ... exhale some more. I'd betchya you've still got some air in there. Push it all out. By the time you've completed your exhale, you'll be a few feet under the surface ... where compression is your friend.
Now, what about your feet? A lot of divers will be kicking and not realizing it ... it's an instinctive reflex. So try crossing your feet at the ankles ... that way you'll be aware of it if you get the urge to kick and can tell that instictive part of your brain to stop doing that.
Finally, relax ... people tend to get "floaty" when they tense up. Think about why you're going down there, and let your mind help your body stay calm ...
... before you know it, you'll be down near the bottom, having fun ...
... Bob (Grateful Diver)
I am thinking of laminating this quote and passing it out at the dive sites, except that NWGD might sew me for copyright infringement.