Your strategy for playing Heroes III.

I'll briefly describe my mini-strategy when playing casually against the AI (I don't play against people because I don't have anyone to play with).
I always build 1 squad of melee units, 1 squad of the most powerful archers, and definitely a Capitol + Castle first, then only troops with upgrades, and only at the end, magic and guilds (this is if the castle isn't magical). If it's a magical castle, it's all the opposite, except for the Capitol + Castle (the AI doesn't know about rushing).