here's the thing about bronze...
everyone who fancies playing a ranked game - even trolls and people who haven't been level 30 for more than a week - starts in bronze. "I know I'm better than this..." doesn't really matter.
to get out of bronze, you don't have to just be better than the average bronze player. you have to be good enough to carry or get carried in every game.
from my recent experience of climbing out from b5 to s5, these are things I recommend you do:
1 - pick 2 roles. be VERY GOOD AT THEM. always queue for ONLY those two roles and make sure you have several champions under your belt that you can play VERY well. NEVER FILL. do everything in your power to carry hard. if you have a bad game, know how to play safe and support your teammates to take advantage of their kills/plays
2 - mute ALL chat. just fucking do it. it won't help you win a game. keep it disabled until you're out of bronze, if not indefinitely beyond that.
3 - for that matter, if you find yourself typing in an argument with your own team, or even if another teammate just rubs you the wrong way, MUTE THEM and do it early. mute them and forget that they're an asshole and continue to work towards winning as a team.
4 - BUY WARDS. no matter which position you play. a single pink ward can last a whole game if the enemy doesn't happen upon it. it's money well spent.
5 - there's no such thing as a champion "too cheap" or "too easy." players like to insult master yi's and others when they snowball, but who the fuck cares? play champions that win. play champions that are broken and need to be nerfed and are so cheap that make people want to shoot something in the face.