"... then close your eyes, take the shot and sink the ball," says the professional pool player.
That is how confident one can be that your alignment is as it should be for the outcome you are seeking.
The lesson I learnt: Alignment does not happen when you are bent over the table, drawing back for the shot. That is too late.
Alignment happens as you approach the table, stand in balance, and bend down with keen calibration.
With all that prework done, you are aligned — and the shot becomes easy.