I found that when aligning manually, the best thing to get in your head was what you were actually trying to achieve. The goal of polar alignment is to get the mount/scope to describe the same arc as the stars do when they move.
Then you can see easily that the movement in DEC is due to your mounts arc not lining up with the star's arc, and you can also see which way you need to adjust azimuth/altitude.
One of the best visual aids in this regard was
this youtube video (the sound is terrible, but the visuals are worth 1000 words). Just be aware that this is for the northern hemisphere, so you will need to swap directions N <--> S
Adam