League

You suck. Deal with it. Heck, I suck. But that’s not necessarily a bad thing. It means there’s room to improve and you just need to identify what is causing you to suck. If you’re willing to take the time to work on that and try to patch up that weakness you WILL get better. Last hitting? Go practice. Warding? Go study. Wave control? Go practice. Item builds? Go study. You have to accept the fact that you won’t get better unless you practice and study and study and practice.

You make mistakes. I make mistakes. Pros make mistakes. We all do and will continue to make them. If anyone tells you otherwise or that they don’t mess up they are bad and doomed to stagnate at their current level. But just accepting this isn’t enough. You need to recognize when you’ve messed up. That way you can work on not doing that again. If you really feel like it was your fault you lost a game go watch the replay. You’ll see yourself doing stupid things.
Some games are still losses no matter how well you do, that’s a fact. Maybe it was your teams fault. Maybe the enemy team is just too good. Doesn’t matter. You can still use the game to improve. Play to the best of your ability. Take this opportunity to play from behind. Practice last hitting. Your map awareness. Anything. Just find something to take away from it.

Objectives. These are very important, no matter what the objective is. Baron. Dragon. Towers. Whatever the goal is you need to do something. Your team has more kills? Okay. The enemy team was rotating and taking objectives while you were focused on kills. They took first tower. They took dragon. They took another tower. And another. Now your inhibitor. You’re suddenly losing. “But we have more kills!” Sucks. Kills don’t mean everything. They are taking objectives and causing pressure because they made a goal and made the decision to stick with that goal.
Speaking about objectives and goals, it’s always better to make an okay decision with the entire team than a great decision while down a member or two. Similarly it’s better to make an okay decision quickly than to make a great decision slowly.

Communicate. It’s simple but effective. Let people know the laner is missing, and which direction they went. Ping the jungler if you saw him through a ward. Tell your team if a vital skill is up or not. Let them know your strategy.