First of all, I need to tell you this: Don't hyperventilate. When one does that the percentage of CO2 reduces and CO2 is responsible to help you understand that you need to resurface. A friend of mine, really good diver, died last year probably due to that.
The training plans depend on your goals, but there are exercises for big wave surfers, for ...
A cheap and fast solution is using saliva.
I use quite frequently in all my glasses (swimming and spearfishing) since ever. It is quite effective.
Water the lens. Spit on the inside and rub it. Wash it.
For spearfishing there are also some film one might use on the lenses (they solved the fog problem in one of my masks) :
A more expensive solution, that I ...