In my opinion its not the amount of games you play. The most important thing is that you realize your own mistakes and learn from them.
Pretty much everything you listed helps getting better, but especially in jungle decision making is most important.
-after every death, take a second and think about why you died. Did you overstay? Did you misplay? Did you gank a lane where you shouldve respected the enemy jungler more?) By answering this question, youre less likely to do the same mistake again.
-when ganking, try to guess the outcome and compare it to what actually happens in the gank
-try to not gank lanes when it doesnt give you any benefits
-understanding the jungle matchups AND lane matchups is important aswell since you need to know if you can win a 2v2 situation with your laner against the enemy laner+jungler if you dont know where the enemy jungler is and theres a risk of a countergank (if you win a 2v2 you can instead look for counterganks yourself)
-try to guess where the enemy jungler is right now and try to guess his next actions (like ganking, drake, invade etc) and compare your guess with the real outcome
-as soon as the game hits the loading screen, develop an early game plan and jungle path (for example, which laners will push und which will be pushed in by their enemy, you can build gankpaths accordingly; can you invade the enemy jungler?; is the enemy jungler likely to invade you? etc.)
-NEVER, ever tilt, you will never learn while tilting and you learn more from losses (was the hardest part for me tbh)
Just some tips which helped me getting better, hope they help you too. I never played that much but i watched a lot of games, but everyone has his own way of learning, so do what you feel best with.
Edit: i wrote about jungle role because im far less familiar with the other roles