What are the best ways to learn about other cultures?

The best way to learn about other cultures is to immerse yourself in the culture. Move there, live there, learn the language(s) and experience the every day over an extended period of time. The above is true, but if you aren't financially able to do this then read everything you can on different cultures or at least one in particular you are interested in. Also choose friends of different cultures and you can learn some of their traditions and they can learn yours. Variety is everything in friendships.