Ok have fun on already started play, and enjoy this great game. As link i said it`s impossible diff, that`s why i asked for your game.
As for my advice, no need for trap 3rd lvl, it`s good for building trap medal, and getting lots of rage skill exp. You can also drop inquisitor number for same reason. I quess you use them for holy rage, and resurrecting ally troops. So tactic is have enough inquisitors to cast 1st lvl phantom on them and make at least 1 new phantomed unit. Then with that illusion revive who you need to (and heal it to full hp for meagre 3/2/1 mana), and use all charges of holy rage. Then with rage gotten that way use mana accelerator pet dragon skill and get more mana for phantom skill, and repeat. This is great way to boost your pet dragon skills, but dont use it all time, it gets boring easy and it`s not easy to do all time (pick some battle that have some range enemy stack that will be easy to control, but dont drop it`s number to low because pet dragon exp depends on ally/enemy leadership ratio).
Also try taking only 1 marauder unit, instead polar bears and use their looter skill (dig corpses for gold), i got around 3-5K gold with it, in the Legend (first game in Kings Bounty series). But there was interesting `Gift` spell that reset unit abilities for just 7 mana (i use to dig up all corpses in battle, and find more gold then i can possible spend

).
... those just some things of off my head. Have fun