Besides in and out,
and don't stop.
I appear to be an air hog, and I am still working on Bouyancy.
Any tips on refining technique would be appreciated. -N
The trick to controlling your breathing is that you can't control your breathing.
Although breathing is somewhat voluntary, the important parts are automatic, and if you consciously modify your breathing, eventually you'll have problems.
The trick to using less air is to use less energy, which will require less oxygen, which will let you breathe less. Using less energy is accomplished by streamlining your entire profile in the water by minimizing danglies and anything that catches water, maintaining a horizontal orientation and moving slowly.
Staying horizontal is made much easier by being correctly weighted, and having the weight distributed properly so you can maintain a horizontal orientation without expending a lot of effort.
So . . . . Get your gear secured, get properly weighted and trimmed, relax and go slow, and you'll be all set.
OTOH, "air hog" also depends on who you're comparing yourself to. I've seen short skinny girls who routinely do hour dives and come up with 2000 PSI left. In the end, it's just air, and if after trying everything, you still come up short, just get bigger tanks. There's nothing magic about an 80 cu Ft tank.
Terry