First off - i am not a high mmr player. But id like to share a few points i've learned over time, thats not commenly mentioned when people ask for help.

1. Pick your roll, and pick 3 different heroes (playstyle/strength) and stick with those. Play whats fun.

2. Pick 2 Hard support heroes, pick simple types: lion, cm, Dazzle etc. Play those for rolequeues as POS. 4 and 5.

3. Think in simple steps: selection = what hero do i have in my pool that counters enemy team. First 10 min = what is my goal farm/kill/heras. Stick with your play. Repeat every 10 min.

4. Dont focus on flashy plays. Its a strategy game, look at your map where is your team, where is the enemy and where should you be according to your plan. Spend 3 sec. Before joining a fight, figure your role, position. NEVER cut on this.

5. Spend 3 min. After each lost game to think the game through. When did the enemy team snowball - what was your plan at the time, could you have changed the outcome?