[2020] How do you get more kills?

This is probably going to sound super cliche, but aim higher. I used to lose a ton of gunfights because I aimed too low. Those headshots are key. The reason you're dying to headshots so frequently is that the people you're engaging in gunfights with are aiming at, or near head level. This is something you can learn to do in T-Hunt.

When you play Siege a lot, you begin to get a feel for where standing head level and crouching head level is. I would suggest running T-Hunts at those head levels and practicing training your aim to consistently be at those levels at all times.