this is because you're a woman

this is the recipe to success for HoMMIII : get a castle and as many unupgraded creature generators in the first week. Hire and extra hero and have the two range as far as you can, grabbing as many loose resources as possible. bring your strongest hero back to the castle in the first couple days of week 2

week 2 is developing a capitol, and upgrading one ranged generator for bonuses, then having your hero travel from mine to mine just killing the baddies while your second (or third, if there's a lot of open ground and resources, but generally there isn't) grabs the loose resources and flags all the mines

week three is upgrading creature generators and mage guild (if you're interested, but level 2 is usually good enough), loading every troop on to your big guy, who, close to the end of the week, you send out into enemy territory to wreak havok.

provided your combat tactics are effective (honestly not that hard) you should easily trounce the enemies' big hero, so they won't recover for another 2-3 weeks every time you bash them. rinse and repeat for great justice. Always keep at least 1 week's troops close to your home base in case another opponent shows up, and even have your second hero clean up the straggling loose monsters to develop some exp, get logistics and become a creature runner. buy a new hero for every castle you take over to flag all the loose mines and build an army from the new castle while your main hero gets reinforcements and heads into the next territory

hero building is always by personal preference, but air/earth magic and logistics are basics for eevery hero type. magic heroes should concentrate on getting wisdom, sorcery and 2 or 3 magic masteries on expert, and combat heroes should get offense, archery, defense and tactics. the rest is all flavouring.