YUGIOH: Any advice on making my elemental hero deck better, its beaten Dark Armed Dragon decks!?

That deck is strong, but I bet my old Elemental Hero deck could beat that. You should add Elemental Hero Lady of Fire and Elemental Hero The Heat and their fusions. Well balanced. It is copying Jaden Yuki's deck. If the dd deck is a deck that removes cards add Imperial Iron Wall to your deck, they wouldn't be able to remove a single card, as for the lightsworn deck, you'll have to try your luck, and by the way, add some more of your most powerful Elemental Heros such as Wildheart, Prisma, and Clayman. I hope that helps you out.