Here are my recommendations:
- remove GarageBand, iDVD and iWeb if you do not need them - that should free up around 6 GB right there
- check out /Library/Printers/ - 2 GB of printer drivers that you may or may not need
- use
OmniDiskSweeper (not free) or my personal favorite
WhatSize (free) to determine what all is taking up room on your HDD and where it is
- use
Monolingual to remove the unnecessary language resources from your Mac
- lastly, you could always use
AppZapper to ensure that when you uninstall any programs that all those pesky sub-folders, etc. are deleted
And with Monolingual, yes, if you are using an Intel-based mac, uncheck all the Architectures selections or else Rosetta, among other things, will simply not work.
That should just about do it.