Good buoyancy control helps preserve the reef.  Best way to help the oceans is to avoid damaging them in the first place. 

Images of divers taking pictures while sitting or standing on coral are all too common. They are not intentionally trying to destroy the reef but are ignorant of the damage they are doing.  The same goes with me when I accidentally drop onto a piece of coral or drift into the reef. 


Avoid dragging gauges and alternate air sources (octo) by securing them to your BCD. Many products such as hooks, clips, carabiners, or re-tractors work perfect. I personally use a hoseless air-integrated computer that I wear on my wrist and an integrated alternate air source. This eliminates the 2 longest hoses, gauges and standard octo, so there is nothing to drag. 
By taking a Peak Performance Buoyancy course I learned the secrets of perfect balance underwater. Can't say I am perfect at it but I have so much more control of my motion underwater.  Perfect weighting, not using my inflator at all if possible, and breathing control makes a tremendous difference. 

Good luck!