Scenario:  righthanded women backup bowler shoots from left side. Average is mid-140's should be  170 with proper skill training.

Habits include last steps in approach include stepping left and overcompensate by throwing ball right.  50% or more of her shots are right of head pin.  Probably shoots 50% or less on 5 pin leaves all resulting from footwork and targeting.

What advise, training tips would you suggest to straighten out approach and shot.  Thinking of using pylons (used during basketball skill training) preventing steps left or use pylon in mid-lane as target guide.  The targets, arrows or trace finders don't work for target shooting.  Any help would be much appreciated.
 

How far left is she?  Sounds like she is too close to the gutter and then has to overcompensate by throwing the ball away from the gutter as opposed to standing a little further right so the ball is going more parallel to it.  Seems to be a little mental block when it comes to the gutter that she needs to overcome and just relax and not be afraid of it.  Does that sound about right?

Sounds spot on, along with compensation for clearing her hips.  Will try to guide her closer to 3-4 arrow as start point.  League isn't until next Wed. summer leaves little time for practice.   Thanks for pointing that out, always identified issue with walking left, throwing right as main problem with accuracy.   Thank you.

One thing you could tell her is to walk towards the target she is looking at.  That way as long as she is in a good starting position; it can help to minimize the drifting left.  Focus on the target and pretend the gutter isnt even there.

I remember over 20 years reading a book on how to bowl, (I think this was mike aulby's) he addressed the back up bowler issue and why it's so bad.

I won't repeat the argument, but the segment ended with him making that point that if this was a legitimate way to bowl well, then there would have been a successful back up bowler at some point. But despite all the people who have tried to bowl this way, there had never been anyone doing this who accomplished anything in PBA, or even known as good amateur. ZERO.

Well that was over 20 years, and finally we did have back-up bowler win on PBA. Anthony Simonsen. And I doubt this person bowls anything like him.

And from my personal experience, being in bowling alleys for 4 decades now, I have never once, saw a good thumb back up bowler. I even just went to Youtube, looking for a video of anyone throwing a good thumb-backup ball. NOTHING, other than some people who can do it for spares.

I understand from a coaching perspective you are supposed to work with what you have...

But if someone is averaging in the 140's, and wants to get better, and is seeking out coaching, then why not just take a step backwards and learn how to bowl using a more reasonable style? So she can get up to 190's, 200's. Not 170.

People have complained that I shouldn't bowl one hand, no-thumb. I used to admit that for most people it is the worst option. But I have to take that back. The absolute worse bowling style in the history of bowling, in terms of producing successful bowlers, is thumb-back up.

I have to agree and disagree with what you said.  What you said makes sense if this person is wanting to reach a more advanced level.  What you said doesnt make sense if this person is only looking to improve on what they have and really have no aspirations to go to a more advanced level.  I have seen plenty of backup bowlers in my 40 years that averaged 200.  At the end of the day it is about repeating shots and being accurate.  Is this something we would teach at the youth level?  Absolutely not.  But if this is something she does naturally and has no intentions of entering tournaments or taking it more seriously; then why not just improve on what she already does?

To do what you are saying can be extremely difficult to do.  You are wanting this person to go completely against all the muscle memory she has developed which could take quite a bit of time.  I went through this with my ex-wife about 10 years ago.  She was a backup bowler averaging about 120 but she approached me and said she wanted to learn to bowl the "correct way".  So what we did, was upped the ball weight from 12 to 14, put her into a fingertip grip, and worked with her for about a solid 3-4 months before everything really started to click.  But even then, her average only improved to about 145.  A significant jump nonetheless but nothing that was going to warrant her opportunities to go to the next level.  One thing we do not know about this lady is her age.  Is she someone who is in her early 20s and would like to achieve an average upwards of 180 or higher or is she well into her 30s or older just looking to maybe raise her average 10-20 pins with a little advice?  We cannot think of this on an Anthony Simonsen level.  We have to think of this on her level.