Reading the thread http://www.cartographersguild.com/tu...ght-place.html is a good start.

Reading a book on physical geography is also a good way. There are quite a few online, including Geography : Physical Geography ( see 7(p) Global Scale Circulation of the Atmosphere for a discussion of global atmospheric circulation ). There are also quite a lot of resources under the topic of "worldbuilding" in your favorite search engine.