Hearthpwn

I'd replaced Primordial Glyph for Babbling Book

If your opponent is an aggro-orientated class like hunter and warrior, you would want to get something on the board in turn one. I would mulligan for fire fly, frostbolt, glacial shard, or even blizzard. If your opponent is more a control-oriented class like priest, you need cards that can generate value overtime. I would mulligan for fire fly, servant of kalimos, steam surger, and so on. Fire fly and the flame elementals serve as cheap elementals to make sure you can play them consistently to get the value, and in the late game, frost lich Jaina is a monster. I have played several games with full elementals on board, and on turn 9, if you are able to survive against aggro, you are pretty much guaranteed a win. I would put down frozen crusher on turn 6, it not only serves as a giant threat on board, but I will also reserve it until turn 9, and heal myself for 8. Pretty much guaranteed a win if you are able to play the hero card. I have even won against aggro murloc paladin, who played murloc warleader with coldlight seer, got 6 murlocs pulled out by finja, and adapted them with both of his gentle metasaurs. I have only lost to one pirate warrior and silence priest so far. During the second game, I was down to my last 6 cards and still did not get Jaina. Sheer bad luck. Overall, I like the deck and it does pretty well against control and crush midrange decks.

Need some play tips with this deck. Missing Jaina and Pyros, but have lost 5 in a row now! Help!

This is the default mage build for this expansion.

Can someone tell me a tip or how you play this deck?

I cant get below rank 20

You probably mean ABOVE rank 20. The deck is kind of bad. Check some decks at Tempostorm or Hsreplay.