If you work too hard on descent you will build up CO2 which will incarese any narcosis, lead to accelerated breathing and may give you the mother of all headaches after the dive. All sorts of other stresses too - so best avoided.
Find a skipper who uses the correct length of shot line so you don't have massively long shots to swim along as much as down.
Tilt yourself so that you are head down and swim along the angle of the shot rather than constantly towards it as you drop.
Take your time. Match effort to breathing rate not the other way round.
Buy a scooter
