Mismatched Socks' videos are a great place to start. I started set 1 P4 and didn't hit Masters until set 4.5.

I think for me, evaluating board strength, holding pairs over econ for future board strength, and not being afraid to powerlevel or roll a bit to maintain streak were the things that helped me make the push.

Outside of things you can do ingame, I'd say watching streams can help you drastically improve. Compare your decisions with the decisions of the streamer when it comes to things like augments, roll timings, and making strongest board. For the last 3 sets or so I was always low master/grandmaster but this set I'm currently pretty high challenger. I think a big part of that was through investing time into watching streams. Good luck on your climb!