There is no easy way to improve accuracy.
you'll need to focus on both the music and the hitsounds.
Using scoreV2 mod is a good way to force yourself to keep good timings.
Avoid hard rock at your level, you'll use it later. (or it will destroy your low-ar reading)
Hitsounds volume, find a good balance, you need to hear them clearly,
not too quiet, not too loud.
Good luck and have fun