The best way to get better and earn a lot of pp is to focus on your aim, speed, reaction and timing. Try experiment mods that can increase your difficulty, how?Lol.
First, find a map that is easy or good for practice and add mods if necessary, HR(Hardrock) is the best way to train your reading, accuracy and aiming skills, DT(Double time) is suitable to practice your speed and HD(Hidden) or FL(Flahlight) is great to practice your memorization and accuracy skill. With these mods, you can master osu! in no time.