There’s one key to hitting a flush iron shot: it’s where the club hits the ground. If you look at a Tour player, their deviation from that spot is a half-inch; a 10-handicap’s deviation from that spot is 3-4 inches.
Using an alignment stick, practice taking swings with your divot taking place in front of where your ball position would be. From there, pull a ball over and start hitting your irons flush.