I have deviated septums and it's very difficult to breathe through the nose even if I wear Breathe Right strips or keep the nostrils moist with saline. This affects both my quality of sleep and my breath control during multiple attacks, etc. I get tired VERY quickly and this gets me frustrated.

Other than mouth-breathing, can anyone give me any advice on how to take in more air without surgery?

I actually have two friends with that problem. I don't think there's a secret technique. Why don't you do the procedure to fix the problem? It's simple, it can be done in any hospital and you'll be a lot more comfortable from then on.

One of my friends fixed his problem and the other one, which is actually also a student of mine, didn't although I advised him to do it. When we practice, while he's performing techniques he almost seems to sufocate by himself. He simply can't get enough air.

I don't think that's worth it just to avoid a simple procedure... just an advice.