Well, whining and blaming your teammates certainly doesn't help. Just watch some of the million promotion guides and just dont give up. Easy as that, now if you want to whine on the internet about how bad your teammates are, then you should take a look at your own individual skill. There are a lot of problems in bronze, but that goes for both teams. Eventually when you're good enough(which you might already be i cant judge you cause i obvs havent seen you play) then you should be able to carry yourself out. This has been said 1 million times so you cant really expect a different answer. Oh and trust me i've had some terrible games in bronze/silver

The key to winning a game when you're are losing is to have good teamwork. And a lot of farming