If you like this game, and you played Homm3 try this out (if you have KB-the Legend)
http://forum.1cpublishing.eu/showthread.php?t=27802 ,
http://forum.1cpublishing.eu/showthread.php?t=29080 (first link is about new things in mod, second link is for downloading said mod)
1) Well things should go easier now with max higher magic, and spamming trap/fire arrow and such. And get that ancient amulet asap, mana and int bonus will help you allot.
2) Learning will pay off later, but on first 4 islands all battles wont give you more then 100k exp i think (dont count quest exp it wont rise with learn skill) so you could maybe get some sills to help your army before buffing hero on low lvls) First problem on start for mage is surviving and achieving no loss as you said you want, second is to improve hero herself. But you managed it so far, things should go better from now on.
3) If you get more royal thorns maybe keep them, but as it is now thay arent of much use. Paladins arent best in dealing dmg but as supporting unit, second wind is great ability (on inquisitor for more rage, on archmages to hit enemy and maybe shock them . . .) Priests dont pay off since they only good to heal and that is 2 mana cost of healing spell in battle, better take some useful army instead of them. As for rune mages, i`m not sure are you playing normal AP or CW ? they are CW units, my bad sorry
But from this trip to Debir you can decide to go full human army with royal griffins and great moral (paladins, horseman, archmage, inquisitor + royals), or to try call collos scroll and go 5th lvl army, with inquisitor/archmage and some other supporting troop (stone skin/magic spring + magic shield from archmages will make great tanks of any unit near enemy. Also try using target spell on your tank, it`s great to pool enemy from rest of your army, and get them on traps
). Try using royals if you go human army, they will have positive moral, and unlimited retaliations is fantastic for them as tanks. Also for getting full army try finding sacrifice+time back/hypnosis combo, it`s great and cheap way to get full lds worth of units, search here on forum.
4) Digging chests in battle is nice way to get scrolls and lots of gold, but i dont think chance% for better reward depends on enemy army strenght.
Pet dragon exp on other hand DO depend on enemy size, so on start when enemy is on full you get nominal exp for skill * (whole enemy leadership/your whole leadership). Expl :you have 1 only red dragon no other units, and enemy have 2 red dragons. Leadership ratio is 2/1 and every rage skill you use will get you 2*exp value of it listed in rage box in skill description, but if you have 1 red dragon, and left only 1 priest alive ratio is 50lds/2000lds=1/40 and you multiply that to exp listed for rage skill so for chest digging of 10 exp you`ll get 10/40=0,4 exp=0. Lesson of story if enemy units are to weak dont use lots of rage, it`s not worth it maybe only chests or mana accelerator but no need to waste rage on it.
5) Trust me there tons of crystals later in game, and take only 1 lvl of neatness skill will be enough to destroy all 1-3 lvl items you dont need and but for low price, you can get 4 magic crystals (=70.000 gold) from destroying 1 3rd lvl item cost 15-30.000 gold. It really pays off later, but done is done.
Try getting red dragons, or trolls(they are great tanks) if you go 5th lvl army. If not keep call collos scrolls for later when you have at least 5000lds for 2 black dragons (you can revive them with inquisitors).
Dont forget cave on scarlet wind there you`ll usually find some nice item after killing that 20lvl zombi hero, but you first need to talk to parrot on rusty anchor to get password for it.
Anyway keep it up and good luck