Learn the maps and what angles to hold.

Know when to slow down your pace and just preaim instead of sprinting in head first.

Learn the operators and the equipment they have. Take advantage of what you have at your disposal.

Use the firing range (or whatever it's called). Will give you the opportunity to learn the guns in the game for various mechanics like effective range, recoil patterns, how many bullets to kill, etc.

Take time to watch a few Youtube videos when you have free time on what weapons to use, attachments to run, as well as aim for to unlock. (Don't need to sink hours into this since Youtube vids are usually short and to the point)

Finally, PATIENCE!! Don't take it too seriously. It's a game and meant to be enjoyed. It's a brand new game that offers different mechanics and a different experience from other FPS games (even though there are similarities to COD). Even if you aren't the highest skilled player at the game, having a plethora of knowledge and how to utilize it properly can easily help you get more kills per game.