Re: 12 - 30 arena ranked
MMR is pretty much a system that decides the amount you get for winning/losing.
The exact inner workings of it aren't known yet, nor do I believe that we're going to get that as it could most likely be abused in certain ways.
The game could put you with other overperforming players if you yourself are overperforming, so based on that it'll probably also give you some different numbers.
Sometimes taking a break or losing some more matches can be the key to get you some more points per match.
Personally don't think you can do anything yourself to influence your MMR directly.
