One thing that helped me a lot with single pin spares was how I changed my approach.  On corner pins, I angle my feet towards the target and this helps prevent pulling or having to muscle the ball in any direction.

For example, on a 10 pin spare, angle the feet towards the right and walk slightly towards it.  The opposite is true for the 7 pin where you'd angle the feet towards the left and walk slightly towards it.  Ever since starting this a few years ago, my percentage of converting the corner pins has gone up significantly.

Then for other spares, you can modify this.  Using the same principle can and usually will help.

What you may want to do with some practice sessions is see if your bowling center will allow you to just have single pin or certain spare conversions set up in the rack.  Have your team do nothing but shoot at those for part of the practice.  By repeating the shots correctly on a regular basis, it will reinforce the importance of spares in a good way.

Gotta practice practice practice

 Maybe have your bowlers shot a game or two of all spares every practice.

In addition to the good advice already posted above, you might want to look this over:

http://bowlingknowledge.info/images/stories/8_steps_improving_your_spare_shooting.pdf

If you need to teach various spare systems, here is a page that has links to various spare systems.

http://www.bowlersreference.com/Approach/Spares/default.htm

Quote from: SrKegler on December 15, 2013, 08:36:19 AM

2d I moved the pins out to the arrows.  Put one pin on the 20 board and one on the 10 board.  Object is to simply roll the ball between the pins.  As they get comfortable, move the pins closer together.

For some reason, in my mind I am thinking that the ball will hit both pins that way.  It seems to me like that is close to being the 5-6 split, but I am not sure what board the 6 pin is actually sitting on so I am probably wrong on this. 

Might be right.  Been quite a few years.  What you want to do is leave about 2 balls width between the pins.  All you're really working on is them rolling the ball straight.  Just an accuracy drill.

Don't let them bowl games and throw strikes..  Practice Practice Practice...  Teach them a spare shooting system, ie) 3/6/9 or Triax...  I use triax..  Urge they get a spare ball and teach hard and straight..

All the replies are good advice on the physical side of the game, but what about the mental side of it? Need to make sure they are treating the spare shot as an equally improtant shot as the first shot. Also, need to make sure even though they did not get the result they wanted on the first shot, the kids need to let it go as quickly as possible and reset themselves to make another quality attempt.

 You can have all the physical gifts in the world, but if your in the wrong mental state, it does not mean much.

  Single pin miss is equal to 11 pins per frame. It adds up quickly.  To me it concentration or the lack of when I start missing. Doubles several years ago brother and I where bowling a tournament we came in like 10-12 place in a really big tournament for are area. We got done an count the single pins we missed an it equal 130 more pins we should have had. Which means we would have won the tournament. It woke both of us up real quick how important they where (Spares). By the way all tips that where given are good one. Just make sure they realize how important spares are.