In archery, if your mind wanders so will the arrow.
The best I ever was as a traditional shot was in the early 70's (17-20 years old). In those days I could visualize a "tube" going from me to the spot I was trying to hit. I began forming the "tube" (the tunnel some refer to above) during pre-draw. Once you get that feeling of zooming in on the small spot you must then take your mind off aiming (your eye will keep it going) and think about something that causes you to follow-through. I think "thumb to the shoulder".
I teach archery to teachers, most of which have never shot a bow. After shooting blank bales at 7 yards I reveal the tareget. The arrow groups get larger. This is because the teachers forget to focus on the "back of the shot" (follow-through). Once the point is made the groups re-tighten. Then I have them put a tiny piece of tape on the target to look at (pick a spot). For most the groups tighten much more then.
You probably already know that if you poke an arrow hole in the middle of a paper plate and look at it, your groups are smaller than when shooting at the paper plate without a hole. You can prove this by not looking at the hole, just the entire plate. This stesses the importance of seeing or imagining that errant hair, shadow, etc. that is in the kill zone of the deer, hog, etc. you want to kill.
Finally, there is another way of aiming without sights that works very well. It is caught "point of aim". There are three parts to it. 1). When you anchor see the bow string in the corner of your eye. 2). Then see the point of the arrow. 3). Put the point of the arrow on, below, or above the target, depending upon how far you are from the target. For instance at 14 yards, the point of my arrow (when I experimented with this) has to be about 6 inches below the heart to hit it. Of course with this method you are forced to pick your spot so you can reference the point of your arrow to it. By the way, then you must complete the shot by properly releasing, following through, and then reflecting on how the shot "felt".
I'm a gap shooter. I must pick a spot and I subconsciously (more or less) see the appropriate gap between the arrow point and the spot. The more I practice at various distances the more subconscious the gap will become and the more I will "think" I'm shooting instinctively -- and technically I suppose that's the definition of an instinctive shooter -- I see the spot and shoot it.
By the way, many veterans (I write this with respect)scoff at this point-of-aim method. I can tell you this. After shooting compounds since 1975, and sights on compounds since around 1981 I began in earnest teaching myself to shoot recurves without sights this past December. I started with point of aim as described above. After a while I was able to consciously ignore the bowstring and even the point of the arrow but I still saw a vague gap. Now, it appears as if my bow arm knows where to be at the distances I practice (14-25 yards)and all I have to do is stare a hole in the tiniest spot I can imagine. I think I've stumbled upon (for me) how to train onself to be a subsconscious or instinctive aimer. The proof for me is when I've comme to anchor and then second guess the elevation of my bow arm by raising or lowering it, I invariably miss high or low respectively -- 90% of the time (or greater) I should have trusted my first "instinct".
Finally, one more emphasis on the archery's form, shot execution, and follow-through. All of these must become subconscious skills eventually so you don't forget to do any of them correctly. One example, the bow arm must be allowed to move during the shot (very slightly) and during follow-through (dramatically). When we were learning to shoot those who told us to "keep the bowarm still, up and unmoving until after the arrow hits the target" told us wrong. This is unnatural and causes us to fight the shot. Trying to do this can lead to all kinds of problems, one of which is a "soft bow arm" which leads to creeping. When I forget to do this (lean slightly into the bow grip)I hit a few inches to the right (I shoot LH). With the drawing hand if I don't think about sliding my hand (very quickly-reflexively because my active back muscles execute the shot) along the face, under the ear until the thumb touches the shoulder, I will hit left.