I play combination bets, but go for an approach called double cover. It basically means making sure that if one bet wins another does not have to lose. A really basic example is betting on black and either 19-36 or top 12 because those two have marginally more black squares. If it lands on a red in the top section, the winnings cover both bets, on a black in the bottom the same, and a black in the top makes a profit.
There's a lot more to it than this, but that's basic idea.