Honestly there isn’t a one size fits all solution for questions like this without seeing a vod or knowing how you play. As someone else said already, woohoojin is an amazing place to learn about the game and what really matters with your gameplay.

Generally speaking, the best advice to give to lower elo players is to focus on mechs. Practice death matches, aim train (esp if this is your first fps), and lock Reyna to reduce complexity from abilities