I usually do one signature bounty and a few dozen bounties from social networks. You can also try it - it's not difficult.
Yeah just keep it simple mate, although when I first started, I was doing kinda 10-20 bounty campaigns at the same time. But almost none have given me my bounty reward, many of project got scammed and etc. Thus, now I don't do much bounties at the same time. Now I am only handling about 5-6 signature bounties. And yes it does give me more rewards than before.