It takes a lot of discipline and proper bank roll management, but even more than that it takes money to make money. If you're doing $10 bets all the time you're not going to make a living unless you're destroying 10 team parlays all the time (which would still be poor BR management).
Ideally, if you had a large bank roll to work with, I wouldn't go over 5% of your total BR per event and would stick to grinding straight bets on ML's, limiting your picks and hedging, and avoiding most props except for the 'safer' ones once in awhile like distance/ou as trident mentioned. I'd also play about 5-10% of your total betting amount per event on a few parlays for upside hits once in awhile.
Lastly, I'd avoid the heavy juice like the plague in MMA. Just look no further than fights like JJ/Rose and Bisping/Rockhold to see how that can go. The risk/reward ratio is absolutely awful.