Two things are key when working on putting alignment.
1.) Proper eye line – your eyes should be directly over the ball in to ensure you are looking down your intended line when looking at the hole. To test this, either use a mirror or place drop a ball to the ground from between your eyes and note where it lands. That should be where you position the ball in your stance.
2.) Draw a line or use a line on your golf ball to line up at your intended target. It is much easier to line up properly from behind the ball than standing over the top of it. Once your ball is lined up at the target, align your putter to that line and trust it. Practice this routine as it may take some time to trust if it is new but it works!