The element test

Your sensei, or a jounin-ranked admin, gives you a piece of paper, you focus your chakra into that piece of paper and if it...

-bursts in flames, you have fire element chakra.
-gets wet, you have water element chakra.
-turns to dust, you have earth element chakra.
-crinkles, you have lightning elementary chakra.
-is cut ahalf then you have wind element charka.

As a jounin you can train yourself to archieve a second element.
if the paper does 2 of the above u r a psychic

also to add something how about having if the paper does two of the above you are a psychic