Disclaimer: I’m not that great of a player myself but I REALLY love playing.
That said, owning and regularly playing games will not necessarily improve your ability. As Cal Ripken is credited with saying, “Practice does not make perfect. Perfect practice makes perfect.” In other words, you can play every day but unless you are practicing in a specific way to improve weaknesses, you will only get better at an ineffective approach. Pinball is goofy this way in that it’s a game that is fun even if you suck. Just enjoy playing, whatever the outcome.
If you want to improve, watch people play who are significantly better than yourself. Watch PAPA videos. Join a league. Figure out so the best players in the league are and play with/watch them whenever possible. Practice specific skills once in awhile like training yourself to allow a dead bounce to regain control rather than flipping on the fly. Practice drop catches, etc.
I bring several approaches to my machines: a training approach where I practice a specific skill, competitive play (playing with a mind geared towards ball control and the rule set of the game) and finally, pure fun play. For pure fun, I find that playing kind of recklessly (frequently batting the ball on the fly, not cradling much) is great chaotic fun even though my score is likely to be lower playing this way.
For your specific games, set reasonable goals for yourself. In WOZ for example, what about going for all the crystal ball modes (improves your aim for the spinner and gives you practice with the various altered flipper multi ball modes). Or just practice hitting the orbits and throne room shot on WOZ once in awhile. (Without good aim for those shots, melting the witch is unlikely.)
But above all, just be immersed in the game when you play. Enjoy the process!