Always think about why you died, why you got caught, why you lost the game overall. How could I have changed that? What should I have built, what shouldn't I have built. Should I have followed my team into that engagement, or should I just have kept farming. Maybe I should have used this skill to engage, instead of starting with this skill. Always question yourself. And when you win a game, don't forget to understand the reasons why you won. Because I did ____ which allowed me to _____ ultimately winning us the game. And so forth.
Were there things I could have done better?
And of course, the answer to that question is yes. Analyze your own replays or deaths. After getting killed, think about why. To me, questioning my own plays and thinking how I could have improved them is what allowed me to ultimately climb.