Grand Dragon: 
Feed any dragons you want with 99 drugs, mushrooms, elements , weapons , etc until their stats turn max (it will automatically evolve when you feed enough)

Ultimate Dragon: 
Feed any dragons you want with 99 of every elements, then feed it " Heal " or " Holy Grass " it will then evolve into an ultimate dragon.

Easy Experiences + Item:
When you completed stage 4, head to the training room. Then Set your Dragons to Attack Mode " Then, Keep ending your turns and your dragon will then attack the opponent. Repeat this and you should earn weapons, items, experience, etc.

Class Combination:
Cross Knight + Knight + Light Armor + Heavy Armor [Speed + Attacks]
Summoner + Summoner + Light Armor + Mage [Speed + Magic Attacks]
Heavy Armor + Heavy Armor + Heavy Armor + Light Armor [Heavy Attacks + Speed]