Last year I decided to see how good I could get with a lot more practice. My normal schedule was 9 hole league once a week and then usually 18 on the weekend, or if I was lucky played both Sat/Sunday. Decided to join the range program at a course right by my house (flat fee for all the range balls I want) and believe me...got my moneys worth. Luckily I work from home, so I would run over on my lunch hour to hit a bucket, chip and putt...whatever I was working on. I tried not to hit balls more than 2 days in a row just because...well, I am getting older, so sometimes I'd just go over and chip and putt for an hour.
Long story short: ended up taking 3 strokes off my handicap last year. I'm just one of those people who have to keep my swing "grooved". It was a lot of work but I did reach my goal of becoming a single-digit handicap. This year I didn't go to the range quite as much (because of weather) and I've kind of fluctuated in handicap. Usually once posting season hits here in Ohio, I've had time to work out the kinks at the range...but this year early spring was crap. So I got a late start and it showed in my scores, but I have gotten the handicap back down.
Main thing I try and do is practice with a purpose. I'm usually working on one or two keys when I hit balls-not just hitting balls to hit balls so to speak. But I do try and listen to my body; if it saying "take a day off" I do.