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.
(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.