Well, for starters, experiment with weapons. The Aerospray is good for grinding experience and money, but it's applications are actually quite limited. Check out the other weapons that you like the sound of, and try to learn with them. Even if you decide not to stick with them, getting familiar with a variety of weapons will help you understand the strengths and weaknesses of the weapons your opponents will use.
Keep in mind that points in Turf Wars are not actually a great way of gauging how good you are doing. It only tells you how much turf you've covered, but covering turf is useless if you can't hold on to it. Instead of points, try to keep track of your win rate.
You might also want to finish the single player. It is a nice low-pressure environment to get familiar with the controls, it unlocks some very useful weapons, and it has a pretty darn cool final boss.
Other than that, well, I suppose the best advice I can give you without watching you play or more specific questions is to look around this forum, and to learn from people you see while playing. Look up capable players on Youtube, learn the usual sniper nests, how to get to the middle of the stage the fastest, the best ways to utilise cover. All these tiny details that you'll refine with experience.
Welcome to the game. good luck and have fun!