To begin, I don't claim to be the best player, but I have a couple of thoughts that may or may not be helpful.
From your match histories and stats, it seems like you are a conservative player who minimizes his deaths and tries to help his team by making smart decisions. You probably frequently win lane by out CSing your opponent, but rarely snowball into big kill totals.
I suspect a lot of your losses involve you winning lane marginally, and then either (1) one of your other laners feeds three or four kills and then a snowballing enemy team ravages around the map, or (2) all lanes go generally even, the game stays close, then your team does something stupid in team fighting and the enemy gets a big advantage and wins.
Both of these situations are REALLY FRUSTRATING and make it seem like there is nothing you could have done to change the outcome of the game. Sometimes this is true. For games in which one of your laners feeds Akali 4 kills by 10 minutes, you may just want to save yourself the stress and admit it's going to be tough to win. In the latter situation, however, you can try to take control of the game and help your team focus on the objectives that matter, and make sure you have a strategy for how to win the game, rather than just focusing on how not to lose it.