If you are missing straight blues the issues in sequence:
(1) vision centre,
(2) are you cueing straight on the feather,
(3) the backswing and delivery and finally if you are hitting in the middle of the white.
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(1) vision centre,
(2) are you cueing straight on the feather,
(3) the backswing and delivery and finally if you are hitting in the middle of the white.