This might seem a bit obvious, but don't be pessimistic in Ranked Games.
Lately, I've seen Enemy teams who very well could have (and probably deserved to) win games except they've had something happen in Champion Select and one person decides to troll because of it.
Last night I was put in that position - I'd already locked in my champion, and then someone decided they also wanted to support. This left me with two options. Option 1 was to troll and make sure that the person who stole my role would face the consequences of their actions and lose. Option 2, the option I took, was to change my Runes, Masteries and Summoner Spells and play Nautilus Top.
We ended up winning the game, and I finished with a score of 14/5/11 with a 50+ cs advantage over my lane opponent and all four of my Allies Honoured me for Team Work.
All I'm saying, guys, is to try Option 2 before even considering Option 1 and you might get a few unexpected wins for yourselves.