For one rail banks and kicks I visualize nearby "equal angle reference angles" using the diamonds.
Here are the reference angles for banking/kicking to the bottom left corner pocket - they connect each 1/2 diamond on the far rail with the whole diamond twice as far along on the near rail:
Of course, I don't visualize all these reference angles for every shot to that corner. For instance, the 2 ball is very near one reference angle, so I'll just compare it to that one:
The 1 ball is midway between two reference angles, so I'll compare it to both of them:
Here's the same technique applied to kicking at a ball that's not on the near rail. Just move the near "rail" (where you measure the whole diamonds) up to be parallel with the target - it doesn't matter if the cue ball is above or below the adjusted "rail".