you get better at aspects of osu the same way you get better at any instrument: play etudes. Stuff like chipstream is perfect for streaming practice, though the song itself could be a little bit better designed since the bpm jumps up way too fast.
You can also make your own etudes if you really want to get better. That's probably the best way as it lets you choose the song, the difficulty, the bpm, and all the rhythms you need, so you don't have to learn some other song.
stuff like shoreline is probably a bad idea. rhythms are painfully stupid.