@steemflagrewards is one of the most important communities on steem. I prefer to look for posts to flag manually every now and then... my fave technique being to look at the SFG post, find a candidate then scroll back to more recent posts that haven't been flagged already.
It doesn't take too long given that I can't spare more than a few 100% flags per week. I think the returns from SFG are also pretty good as far as I can remember.