Love your attitude friend. You're already half way there. No joking here, this is the best attitude to have if you want to improve. Stop caring about winning/losing games and focus on your own mistakes, and on how to improve those mistakes so you won't repeat them.
Get LoLReplay and look through your matches -- wins as well as losses, type down your mistakesn in a document or on a pad, remember them and work on not making those mistakes again. Focus on one big problem at a time, and focus on either laning or jungling, take it one at a time. I don't know your goals, if you want to get in a team and play competetively or just be high ranked in soloqueue, but focus on one role at a time. Find out which you want to be best at if you want to get in a team; or just work on your overall mechanics and decision-making if you just want to be high-ranked soloqueue.
Mechanics are important in this game, work on them. Decision-making even more so, every time you make a doo-doo, write it down and write down what you should've/could've done instead. Work on not doing it again in future games. Take one mistake/problem at a time and you'll eventually get there.
Soloqueue becomes fun when you stop caring about winning or losing, and focus on your own gameplay and improvements.