There i lots of criteria to choose the right bounty so you won't be wasting your time:
1 - Chose only SOLID & PROMISING ICO / Projects.
2 - Do as many bounties as you can (they are profitable if you're smart enough).
As for how to get Twitter followers, it's easy, just go check those Follow & follow back FREE websites to get fans, by the time you'll be having 10's of followers so easy, yes this take time but totally worth it.
Your two criteria are contradicted to each other and I think being a smart bounty hunter would not only choose the solid project because in the past few months, bounty and ICO failed or scammed the participants even it is a solid project. We should look for other campaign also since there are no rules in joining multiple campaigns as long as you are not cheating.