I’ll give you some advice that someone else gave to me.
Pick a small handful of heroes. I’d say around 5 max. Limit yourself to those heroes pretty much exclusively. Ranking up is a lot about consistency. It doesn’t really matter what role or hero you play, if you play them consistently well. I’ve pretty much one-tricked Anduin from bronze to near gold.
Another thing is only play a few ranked games each day. Your mindset really does a huge amount in affecting your performance. If you are tired, stressed, tilted, just don’t play. You won’t be able to play at your best level then.
Good luck!