A useful phrase you can use if you travel Latin America is...Deme dos con todo :)
Say you get hungry and suddenly you smell something yummy walking down the street. You´ll probably find a stand with a crowd around waiting for tacos or arepas or empanadas, doesn´t matter. You get there and say, deme dos con todo, and they´ll hand you a plate with something delicious. So it´s always good to ask for two instead of one right from the start!