Looking at your match history, your average KDA is 2.32:1, with a contribution of 38%. Lot's of Cho'gath games, a bit of Warwick. Personally don't like Warwick for low mmr, too much risk without enough reward behind it, but Cho's a good pick.
I might be misreading the match history, but you seem to build full AP cho'gath, top lane and support. Viable, but typically top laners need to be remotely tanky, and support should have an income item, and a sightstone. Deathfire touch is an interesting choice, but I do believe there are better options.
In general, I'm questioning your builds. You're runes are iffy, but work. Masteries aren't bad, albeit slightly limited. While you may not have the best teams, you aren't completely free of blame here. You could stand to improve.