As some one who recently started at 3.2k and is at 4450 and still climbing at a 58% win rate mid 3ks is a weird place to climb. Basically have to be able to take over the whole game at that tier. No one can farm properly in that tier and looking at your record totals / per minutes this patch I can see I'm some what right. Being able to properly push lanes in time to farm a jungle stack while playing carry and getting back to lane with out missing a CS is a huge.
Ignore the stand offs at mid lane where teams stare at each other for 2 minutes until people slowly start to leave. Have TP farm and come to fights the seconds they start for real. BoTs are extremely good at that tier if you have a hero that can flash farm well. Being able to TP anywhere for fights / farming is great. This also adds split push that the other team would have to deal with. This can lead to team fights where your team has more numbers or catching them as they back up to TP.
Be vocal when your team has advantages make sure they push them. Before each game looks at the team comps determine the best possible way to win. Is it to dodge fights for the first 20minutes and farm or is it to stop the enemy from farming. Do you need to win in 25min or do you need to go later then 40 minutes. Relay this to your teammates.
Side note why does your BKB change slots so often. Also go force staff before refresher on Tidehunter it allows for easier ravage refresher ravage. Since at lvl 16 you basically have to have 100% mana to do it with out force staff. Then just overall map awareness. The difference between counter gank TPs at 3.5k compared to 4.5-5k is absurd.
My best method to increase MMR though is play every position change what you do. While you do this remember every time you got mad at a teammate for something they did. Like stupid support didn't do this for me. Then when you play support do what you wanted your supports do. This will make you mad at stupid carries now you know what not to do on carry and mid and offlane etc. Even just playing offlane you learn simple mistakes supports make. Like trying to harass close to the creep wave. Bad supports get hit by creeps fucking up the creep placement while good supports walk out of range and properly zone out offlaners. It's simple techniques you'll learn every game by not just you but mistakes of your teammates and strats the enemies will try.