Well, I already gave you few suggestions in above post. Here are few more.
1. Die as less as possible. Unnecessary deaths reduce your GPM, XPM, KDA and stats. To increase all these important stats, there is just one factor to consider. DO NOT DIE.
2. Spam your best hero as much as you can. This way, your winning chances will increase and your stats will also increase provided you play good with that hero.
3. Even when loosing game, do not lose hope. Keep trying. You may lose that game but your stats will improve.
4. Once you start your calibration matches, keep an eye on highest MMR and average MMR. That is your clue about your upcoming MMR.
Hope this helps.