Every green you hit is a practice green if you want. I like BPB #2. Just get to a green and putt back and forth to learn your putter. You have 10 strokes per hole before you max out which should give you 7 putts, or so. The same idea works for the rest of your clubs, too. Hit into traps, out of them and back in, etc.
Practice rounds don't affect your average, just the scored ones. GL
YJ