Use what is written below to help you focus on what you will need to become a better player:

At all times you should be working on two things: map movement and map awareness.
Map movement is the ability to quickly and effectively move across whatever map you are playing in, and map awareness is the ability to predict the movements of the enemy team/player(s) so that you can devise counter measures to their poisitions.

Lvl 1-30 players should focus on experimenting with the weapons they unlock and rather than build loadouts right away and should mostly use the weapons they feel they are best with in order to attain levels

Lvl 31-70 players by now should know which basic weapons they are good at and should be focused on beginning to develop loadouts that best counter loadouts used by enemy players to achieve victory conditions

Lvl 70-80 players by now should have decent knowledge of most weapons and how to use them and should by now stay more focused on reaching the veteran status and work towards getting whatever weapons are left that they dont have

and finally lvl 80+ players should by now have accute knowledge of their weapons, tactics, counters, and loadouts and should be more focused on developing more advanced skills to use with various weapon loadouts. Such skills can be advanced sniping skills, movement skills and any other skills that they feel they still lack in order to become more proficient players in the game.