1) Consistency through the bag, from round to round, and from hole to hole. I have the ability to play really excellent golf. I'll go through 3, 4, 5, 6 hole stretches feeling totally in control, hitting most of my shots exactly like or very close to how I imagined with clubs all through the bag, ringing off simple pars, maybe with a birdie thrown in. But I'll hit big blocks and big pull draw/hooks too, and just generally have too many shots that don't go very close to where I'm aiming them.
2) Accuracy with mid and short irons. Mine isn't even close to a scratch player's.
3) Fewer huge misses off the tee that lead to OB, hazards, or jailed shots. This has gotten much better for me but still isn't close to scratch level rarity.
4) Better putting. I feel pretty confident around the green most of the time, but on the green I'm very streaky and will have a bunch of 1-putts and 1 or often more 3-putts and usually more 2-putts that should have been 1-putts than you'd like as well. I'm not awful. Just solidly mediocre and well below average for a scratch player.