Thread:CyBeRdrgn/@comment-5354013-20130824222931/@comment-10090661-20130826065735

(Y) Check out the Elements pages for tips. The pages will be up to date as to the weaknesses.

Summarized, it says: Use a Dragon whose Primary Element doesn't receive critical (double) damage from any of the opponent Dragon's Elements, but (your Dragon) has an Element deals critical damage to the opponent Dragon's Primary Element.