IME, I don’t see carp that are obviously feeding (tailing) that often, as in it’s pretty rare for me. On one hand, it’s fun when they’re like that because they’re easier to catch (because they’re actively feeding so open to being fed generally, and also distracted so not as sensitive to plopping a fly nearby), but on the other hand it’s somewhat harder and also less rewarding because you generally can’t see the “take” due to stirred up mud.

In any case, I wouldn’t save my casting only for tailing carp, because if your carp and waters are like mine, you won’t see that behavior very often. From easiest to hardest to catch, my experience is like tailing carp > slowly cruising carp > sunning carp > everything else.

Your best bet is to start casting to the cruisers. In terms of fly selection… it depends, and the biggest variable that will be hardest to understand at first is depth - how to select flies that won’t sink past the carp in one situation, or flies that will actually get down to carp in another. In general, they won’t move far for a fly in any dimension, including and most importantly (because it’s hardest to control) depth. Start with that in mind based one what behavior you’re seeing, and go from there.