On a normal deceleration to a light/stop, let off the gas and leave it in gear to let them motor help slow the car down. Or use neutral if you're coastdown distance is further.

Downshifting is hard on the synchros/blocking rings. I rarely do it, don't see the need. If you insist, tap the throttle a little, in neutral, to get the sychros spinning and then downshift.

Remember, best shifts and minimal wear is when the gear you're shifting to is matched with the road speed & rpm.