Parlays are generally sucker bets. People love them because of the odds, but expecting 3, 4, 5 things to hit isn't sound strategy. Unless you get boosted odds like Rafters mentioned.
You're better off sticking to your one offs that you're confident in.
I'd make the switch to FD if I were you. They run regular promotions and boost odds often. I'm up like $600 on just boosted odds/promotions from them already. I've been hitting pretty well on NBA. Best bet so far was Donovan +700 to score 40+ the night he went for 71. I've cashed out over a grand on there already, and that's with fairly minimal betting.