As an official nearly sub 9 solver, work on your finger tricks early so that they don't become a problem later. To be sub 10 I would say you need to average 6+ TPS and better finger tricks will be a huge factor to getting to that point. Work on cross efficiency as it makes planning first pair much much easier. Learn full 2LLL, and also just go to speedcubedb and go through all the advanced F2L cases, you don't need to memorize them per-say but it's important for you to know what efficient F2L solutions look like. You can also go to reco.nz and look at the reconstructions of top cubers solves like Tymon or Xuanyi which will also give you ideas of what efficient crosses, Xcrosses, and F2L looks like. In all reality though, if you can plan first pair, sub 10 comes pretty naturally, good luck!!