You can use
WhatSize or
Disk Inventory X to see what is all on you disk. Then you can clean up some space removing stuff or programs you don't use.
AppZapper and
AppDelete are both good programs for removing programs.
Monolingual can get rid of al the extra language files you don't need. They total almost 2 gb by them selves.
You might also consider an external hard drive to store things you want to keep.
