Most folks I have seen, if they play in leagues, they dont go to the pool room to practice. They only "table time" they see is league night.
Generally, IMO, league players are not really looking at what they need to do to improve.
If you want to improve I suggest the following.
1.) Get a coach, and have them review your mechanics and alignment. Practicing with poor mechanics is ultimately making you worse.
2.) If you are really a beginning player, learn all the bridges, open, closed, bridging over a ball, off the rail, etc. Along with this, learn to shoot off a mechanical bridge (hardly anyone in league play does this right)
3.) The silly advice of playing someone worse than you is crazy. Play better players and have them critique your play. Specifically patterns and shot selection. (I personally win ALOT of games not because I am a better shot maker, I win because I play smarter)
4.) Safety play. Huge. One of the best players in my home town would come to the poolroom and practice safety play verses making balls. In league play, with a low handicap, if you can play a safety at the appropriate time, you will win alot of games.
5.) The coach I had told me that I would never beat her. I asked why and she said, "Table time." She played hours and hours each day, and I played maybe an hour or so a night on my table at home, and then some on the weekends.
I wish you the best of rolls,
Ken