teach english or something else (another language, music, farming, swimming, any specialized skill, etc)
babysit / nanny / au pair
if you know anyone that lives in the place you’re going, ask about setting you up with something or giving you a contact for the kind of work you want to do
decide on or design a career that’s based in or includes travel – as above, travel writing or photography (like for National Geographic), or journalism, anthropology, ethnomusicology, certain types of political work, performance of some kind, etc
decide on or design a career that can be done anywhere, perhaps otherwise a work-at-home job – get hired or get grants or whatever type of funding you get – and travel as you work – writing poetry, website work, an unlimited number of possibilities these days