I main support, and even though i did great in almost all my preliminary games i got put into bronze V? How does working your way up work? Is it based off of kill death ratio? If so, I obviously don't get much kills.
Ranks and LP gain and lost are only based on W/L and your opponent's hidden MMR compared to yours.
If you played ranked last season, you were probably placed a few levels lower than where you ended last year. The system is made for you to climb, so they may place you a little lower than you should actually be at.
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The initial placements are all based on the MMR of the teams you are fighting. Then of course after that, the matches just matter on who wins/loses.
For a support main, I say things like 
are all fairly great ones that can help a team out massively. I for one went from B5 to BII with in season 3 (2013). So it's possible, but does take a lot of work to get into the flow.
