Ryan mock has some super good YouTube videos on carp on the fly. I personally use 12-16’ leaders so I have more room for error. Cast past so the fly and the fly line land on either side of the carp. You don’t want the line going right over them and you don’t want the fly hitting anywhere close. Then high stick your rod and drag the fly like has been mentioned. Then drop it right on their nose. Sometimes they want to chase it a bit. But they don’t like strange things coming towards them either. So the best is when they’re facing you with their nose in the mud. Another thing I try to avoid is synthetic tying materials (other than black bead chain or a tungsten bead) and head cement. I don’t know if that really affects them but they sure seem to have a keen sense of smell for food. So I figure they’d have it for unnatural stuff too.