I disagree with what most people say about climbing in low ranks. Most people try to tell you that you need to pick a champion that you can carry every game with and don't need a team. Everyone in bronze thinks the same way. Most people in bronze want out and try every game. Pick champions that can support a team and you will destroy in team fights as long as you can take charge and be a leader. I started in bronze in season 4 and easily climbed getting almost 30 lp per game and only losing a couple games until I was in silver. This was done by using unpopular champions who could easily carry by assisting their team, not solo carry the game. Those champions were Galio, Sion, and Rumble. Rumble and Galio both have (had in Galio's case) ultimates that can easily turn a team fight and Sion was basically a second jungler in mid lane. I don't know if you played before Sion's rework, but he had 180% AP scaling on his Q and W combo with something like 700 base damage. W was the same as it is now except way stronger because the scaling. He could walk into lane, blow up the entire wave, then run to top or bottom lane with mobility boots and the highest base speed in the game. This would get his team a massive lead before anything happens and it was usually a surrender at 20.
If you like support, that is a good roll to climb with. As a support, you don't have to worry about csing allowing you to pay close attention to the map which allows you to ping your team whenever you see something. Something can be the location of the enemy jungler, respawn timers for both jungle camps and champions, teleports, and missing champions. Ping whenever someone isn't on the map to warn your team. This also allows you to predict jungle movements once you get used to it. If you see the enemy jungler gank top lane at level 3 with 1 buff then you can assume that they will take about 2-3 minutes to clear the other side of the jungle and get their buff before doing anything. You can then time this and play safe when that time comes in bottom lane.
Control wards are important. No matter what your roll is, you should always get one. Supports and junglers should always have one both in their bag and on the map which is something I actually need to work on as a support main. I usually place one and then I don't buy a replacement preemptively to immediately replace a destroyed one. I sometimes wait until it is gone to get another one. I have noticed that when i queue for normals with my bronze friends, I will have 4-6 control wards and almost everyone else will have 0. No control wards ever is a big no-no if you want to climb the ranks. To give you an idea of what warding is like at higher ranks, my last ranked game had 173 wards and 15 control wards between both teams with 37 wards destroyed and this is only in gold elo. Your last ranked game had 103 wards and 2 control wards placed with 2 wards destroyed.
You don't have to actually be mechanically better than people to win. You just have to make smart choices and become a leader to make choices for your team. If you are out numbered, don't fight. If you are by the enemy tower, don't fight. Never chase someone for more than about 5 seconds because they likely are running to a teammate. Finally is the biggest problem people have in low elo. This isn't team deathmatch in CoD. Kills don't matter. Don't fight if there is nothing to gain from it but kills. Always ask yourself if you can take towers, enemy jungle buffs, baron, dragon, or inhibitors or have to fight to defend one of those from the enemy. If you are in the middle of river with no wards around to see what is going on, no minions pushed to towers, and baron and dragon both have 2 minutes before they are up, why are you fighting? You are fighting to get kills in this situation which won't win the game. By time you get to a tower you will be low health from the fight, the enemy will respawn before you can take anything, and they will kill you to turn it around.
That brings up the next point. If nothing is happening, don't do nothing. There is always something to kill to get gold. If you are walking by krugs and there is nothing happening, then take krugs provided that you have a champion who can. If there is a minion wave that is just sitting there, kill it and then rejoin your team. A minion wave sitting in the middle of the lane doesn't help your team. You need minions to take towers after fights as I said in the previous section. Push a tower, join your team for a fight that you can actually do something with, then go back to the lane that is pushed to take a tower or two. Don't just sit in middle lane staring at eachother's parts waiting for something to happen then do it again a minute later with the minions still in the same spot they just were. Make sure your team is aware that you are not there when you push lanes though because they likely aren't paying attention to notice they are outnumbered.
I hope this guide that got longer than I was planning on helps. I will link a video to the game I talked about with 173 wards in it after it is done uploading to youtube. I thought it was a good example of how a support can control the flow of the game.