What part of the ball do you aim at?

Could you be more specific ? Putting/Irons/Wedges/Woods/Driver Setup/Impact Full swing/Chip Draw/Fade/Straight Shot

lol, don't let him rattle you with TMFI. Rick Shiels on youtube is a good place to start. he keeps things a bit more simple then some pros spitting out 15 thousand things you are trying to keep straight. or you will do like I did the other day on the course and have every bit of information flood in trying to make adjustments and corrections.

if you want a very simple answer for the typical shots (full) you want the bottom of your arc to be shallow behind the ball starting up when hitting a driver.

for irons, bottom of the arc should be a few inches (about 2ish) in front of the ball. thats where you want to see a divot. (this is for most people but I tend to be a "picker" or a "sweeper" and don't usually have a divot but am slowly working on it.) lay a small object in front of the ball like a broken tee or the like. something that aint gonna damage the club or hurt someone. place it a couple inches in front of the ball and work on bottoming there and making that object move. the ball just gets in the way is all.

those other shots he mentioned are something else requiring stance and swing adjustments. but get these two down first or you will flood your brain and over think every swing.

https://www.youtube.com/watch?v=3CAmK1TTN-8 (3 key points)

https://www.youtube.com/watch?v=A1CGjXw_tSc (perfect golf strike)

https://www.youtube.com/watch?v=FFbkkOzA2-Y (if you are having issues with topping)

Ditto

I started to aim the about one inch in front of the ball. It makes easier to focus on steady head thing during backswing if I have aiming point. Previously I just looked the ball without any specific point and it caused lot of unnecessary head movement (with other faults which moves my head too)

If anything I look at the turf in front of the ball, and I am not even sure if I do that. I never think about it. I hit all my long, and middle iron just a bit on the thin side. My shorter iron I don't hit as thin, but I don't take much of a divot with them either. I just give the turf a shorter hair cut with my shorter sticks.  I play most of my rounds in the desert southwest and quite a few of those courses are not user friendly when comes to taking divots. This is also a carry over when I play on softer fairways. I lose a little distance doing this I suppose, but it is what I do.

I suppose my impact spot on the ball is the lower left/center, rear quadrant due to my inside out swing path. I don't consciously look at that spot on the ball though. The ball is just there, and gets in the way of my club face.