General gameplay tactics and its features.

Hello! I've known the game "Heroes 3" for a long time, but I don't think I've ever played it at a high level. So, I want to ask a few questions: 1) What's the best way to start building any castle? (Personally, I start by building the "Town Hall," and then continue in the same vein until I reach the "Capitol." Basically, I focus on building up the castle's economy. Or, I build archers or other units first, so that I can gain experience and money later.) 2) No matter how hard I try to play well, the computer on a high level always seems to be ahead. How does it develop so quickly? P.S. I'm playing as the "Bastion" faction with the hero Ivor.