Assuming you play "right-handed", you'll want to focus on that hand for classical pieces or anything that requires arpeggiating. Too often we take that hand for granted and just expect it to do it's job. As a side note, we likely place emphasis on the left (fretting) hand because it's more visual but let's not forget the right hand plays an equally important role.
It's frustrating for me when I'm learning a piece and the notes come out fumbled. This is a right hand issue. When we can not play a passage accurately and consistently, the best thing to do is to write out the right hand fingerings (P I M A), so that you can see the logic and practice something concrete.
In my preparation of Clair De Lune by Claude Debussy (Impressionistic composer), I found myself stumbling over the same passage without fail, or should I say with fail! With all the r.h. fingerings planned and written out, this will allow me to learn it so I can play it perfectly every time.
I hope you enjoy playing this beautiful excerpt that will get your right hand dancing over the strings!