I found that I can shoot pretty consistently up close, even if my form is weak. I suppose that's because the short distance tends not to magnify those form errors. But when I get to 30 yards and beyond, inconsistencies in form (especially in draw length for me) greatly affect my accuracy.
I've started carrying a longer shaft with me, with a zip-tie placed strategically at the tip end, that bumps my finger when I hit full draw. I draw that arrow from time to time while I'm shooting (but never shoot it), to remind myself how full-draw is supposed to feel.
I spend most of my time practicing between 20-50 yards, working to keep my form good, and find that the accuracy developed at those ranges really improves my short-range shots. I would opine that the more you work your brain at those longer distances, the better it will become at calculating how to make the arc of the arrow intersect at the target.
I have taken to throwing a tennis ball out in the yard and shooting it all over the place. Within 10 yards, I probably hit it 70% of the time last night, even though I don't practice short-distance shooting much. Out between 20-40 yards, I was very close on most shots, but only hit it a handful of times.
I don't really gap shoot, although I am not purely instinctive either. I think that I probably employ Howard Hill's "split-vision" method more than anything. After not shooting regularly for a while, my accuracy really falls apart, but when I get back into shooting regularly, I do OK. I spend time every day exercising my muscles, as well, drawing multiple times to full draw, and then letting down, and then drawing my bow with the other hand the same number of times, for muscle balance. I find that the more I can manhandle the bow at my draw length, the more control I have over my shots. I have been shooting my 68# limbs for the past few weeks, and as my muscle strength has increased, so has my accuracy.