I don't know if there's a better way, but it only seems logical to me that the basis for sight reading is to knowing what the notes are when you see them. I know some people use flashcards to help them learn too.
If you have an iPhone or iPod Touch, there are sight reading training apps too. I'm an interactive learner... I have to be engaged in an activity to really learn something. Just studying it off a sheet of paper does me no good at all, so I like these sort of game things to help me learn.