Aside from the very cliche E-major, F-major, G-major thing, try playing around with:\nE-minor, F#7, B-7, E-minor.\n\nOn www.classtab.org you can download tablature for lots of classical guitar pieces, including a lot of spanish/brazillian sounding things.  Look for pieces by Heitor Villa-Lobos.  You can listen to the midi files first, and then look at the tab to see how to play certain parts.