hard disk storage help

Hi there, I would love some some advice about my best options for dealing with a Full HD...

I have a MacBook Pro running Yosemite OS X 10.10, and no matter what I delete, I can't seem to free enough space on the HD ...

From the 250gb drive the two largest culprits seem to be "other" at 93gb and "audio" at 73gb - I figure ideally the best way to free some space would be to store my iTunes library in icloud... but I can't work out what my best option for doing this is, or how to do it...

I have around 900 albums in iTunes and many of them were originally burned directly from CD's into iTunes, I have iTunes match, but it doesn't seem to match all my tracks as many are classical/opera. I would like to be able to access my music from the icloud easily, opposed to just storing them on an external drive... but i suppose my computer is too old (2015) as I don't see the option commonly suggested in forums to just "turn on the icloud library" from the general tab..?

I am not that confident with technology, but I would love any easy thoughts and helpful ideas on how I might be able to solve my space issue... most forums say the "other" is impossible to get rid of, so I figure working out the iTunes storage is my only option!?

Thanks in advance : )