That can be a tough spot to be in. There are hundreds of little things to improve upon to really help you thrive.
Macro tips for League in general:
Understand how team compositions affect the way the game plays out and where each team has strengths and weaknesses.
Use wards.(That means both placing AND looking when champions walk by. Also to help your teammates literally ping on the map everytime you see an enemy champion with anyone's ward. Literally on average this is worth at least 3 kills.)
Understand when team's(both yours and theirs) could be considering objectives.(Dragons, towers, and barons.)
Trade objectives when behind.
Learn how to abuse enemy players who choose are stupid.(Seriously, there is an ENORMOUS amount of people making dumb plays in low brackets. Farming the jungle when they should be pushing or recalling. Pushing a lane by themselves later in the game. And pathing through an unwarded jungle.
Learn how to snowball when ahead.
Learn how to cauterize the bleeding when behind.
Learn how to find opportunities to get back in the game.
Find 1-3 champions that really resonate with you and your playstyle.
Avoid making negative comments about players who are trying. If you have a top who is 1-6, that's okay. Don't harass him, encourage him to build and position correctly and simply do his role in the game, that makes a HUUUGE difference on the outcome of a game.
As a mid-laner try to pick a champion who can shove lane and roam well. That is super important in almost all elos. For instance, 
is absurdly good right now. You have good wave control, great late game, and fantastic roaming opportunities.
When you jungle, try and think about which lane is the swing lane and seek to snowball that lane.
Also, when you start to tilt in a game and die, get up off of your computer and grab a glass of water. Seriously, this is a great anti-tilting tool. Also, if after a game you are tilted, take a 20-30 minute break. I highly recommend going on an actual walk. It helps clear your head and think about the game seriously. Finally, when you get on a 3+ loss streak in one session, end the session. Cut your losses, it's okay to have some days that end badly, having a stop-loss is a great thing.
Good luck and have fun.(And having fun is very important to climbing too.)
