most of the space hoggers are mentioned already: printer drivers, languages, apps.. you can also snoop around Library folder to get rid of other stuff, like Modems (if you don't use'em), Receipts, Caches (will build over time anyway).
you can also try Monolingual, but if you're on Intel and are using Rosetta, do NOT run "architecture" (unless you wanna find out the hard way😛 )