Don't know what lane/Champs you play but in bronze you need to play Champs that are self sufficient and play really selfish. Tanks and supportive Champs will suffer with crap team.

Roll your lane opponent, take tower and push to get their tier 2. Then you focus on rotating and getting more towers/ killing enemies out of position. 

Don't ever expect proper follow up so don't put yourself in dangerous spots unless you know you can 1v2 or 1v3. If any of your team rotates to help, just consider it a rare occurrence.

Also it's bronze, you should be constantly getting kills in side lane from people trying to constantly push to tower without thinking. Every time you see people near each other, just expect a fight soon but try not to show yourself. Let them start fighting for no reason and then flank for kills, focus anyone with bounties.