Suggest the following:
Either -
If the ball is a little high in the head pin - move your feet 1/2 board left
OR
If the ball is a little lite in the head pin - move your feet 1/2 board right

Good luck!

What always helps me is move your feet BACK about 3-4 inches. Do not move left or right just move your whole stance back. Hope this helps but it hink it wll cuz i just got home from bowling and i was in the pocket everytime and then i moved back and it helped.

one good tip my coach always told me if ya leave the 10 move one board right right if ya leave the seven one board left

http://www.bowlspot.com/page/tipOfTheMonth_tip_072008

Its like this, If you keeping leaving 10 pins and 7 pins, it means your either coming up light and the 6 isn't taking out the 10 pin. with the 7 pin, if you hit the pocket just right and you see the 4 pin go right in front of it, it may have been a liitle high. If you play a line that will get your ball dead in the pocket every time without leaving a 10 or 7 pin, you should be just fine. Just keep practicing. All you need to do is adjust a little and you'll be ok.