http://imgur.com/MYuZc
In those 15 games, I've had ragers, leavers, intentional feeders. 14 of those games I've played Top/jungle (only loss is when I had to support), so I've had an influence on the lanes/middle specifically. Here's how you get out of 1200-1600 (i've also lost about 50 elo to decay due to loss of internet)
1. Play champions that you are comfortable, that excel at roles. In this Elo range, wards are unheard of. If you're top, play something with heavy roam potential. Renekten/Lee Sin/Riven/Gangplank. If you're jungling, pick a champion with fast clear times, good counter jungling potential and ganking potential. Phoenix Udyr, Maokai (can counter jungle wraiths VERY easily), Shyvana is hit and miss.
2. If you're playing mid, synergize with your jungler and vice versa. Get your mid farmed and teams will surrender at 20 minutes. I played a game earlier where I went Warwick jungle, because I saw we had a Malzahar middle. Double suppress was getting a kill every time.
3. Early oracles if you're jungling in case they do have wards. Play smart. Once you blow a flash, set your tent up in that lane and harass it over and over again. Keep control of Dragon at all times (pink ward it yourself if needed). This is your job as jungle.
4. Hit every last hit. Gold wins games. Gold wins lanes. It's all well and good saying "my team sucked", but if you can't get over 100 CS at roughly 12-13 minutes then you're probably in the right elo range.
5. Don't just follow guides. Itemize for your lane first, then the game second. If you itemize against your lane, you will have the upper hand to then buy items to directly influence the game itself. For example, you're Galio top against say, Riven. There is 0 point stacking MR early because Riven will just continue to tear you a new one over and over.