Alignment. Any tips?

I've a couple of points here so bare with me.

First of all, after 4 lessons with my local pro, I've started to fix what he said was my biggest problem: Alignment. He said my bad shots come from bad alignment and that I'm hitting very consistantly when aligned properly, because good alignment means less correction during the swing.

He told me about picking a blade of grass (or some other marker) in front of the ball that lies in line with my target and to align my address to that imaginary line. I've been doing this recently and, yes, I have seen my scores some down. (I scored a 91 on a long full 18 hole course recently having never broken 100 on such a course)

Have any of you more experienced players got any other tips for good alignment. 

My other point is this. Most books and on-line lessons tell of using an 'Open stance with an open club face' when pitching short shots, anything up to 100 yards. I've always had trouble with this. Especially when trying to practice bunker shots. 

Why, technically speaking, do we need an open stance & open face for these shots? Does it not enchourage an in-to-out swing plane. I can understand that the club face will meet the ball still in line with the target but again, why not line up with a neutral stance and an aligned clubface?

This is an interesting topic. I have never taken much time in setting up to the ball and yesterday I thought I would try this lining up with a blade of grass or whatever in front of the ball.

I actually used a previous divot, so placed my ball exactly in line to where I wanted to aim.

When I then set up to the ball looking at both the ball and the divot I got the impression that I was way open in my stance and that I could not see how I was going to hit it straight, and I was right, completely a waste of time for me.

So the conclusions are that I obviously play with an incorrect setup and have done all my life.

Would you be able to put a tee peg or a ball marker on the turf in front of you? Or would this infringe any rule. Would it be allowed on the tee as the ball would not be in play?

Dave CAC handed Geordie.

Dave its againts the rules and is also as bad as sharing a putter all the way round