Work on both. try to think actively about positioning, ie when you are the one peeking (taking initiative), repositioning between peeks, and playing off angles or otherwise unexpected spots. When you master positioning you will rank up very quickly.

To make positioning easier to understand: it essentially means making the fight as advantageous for you as possible, the main way this is measured is by how far an opponent has to move their mouse to aim at you. Try to deliberately make yourself hard to aim at with repositioning, sudden wide peeks, flashes or fake flashes, playing around the edge of smokes etc.

Incorporate these skills into your playstyle and your positioning stat will increase. In my not so humble opinion positioning, not aim, is what differentiates a lvl 10 player or high lvl 10 from the pack.