Live and learn
it's what we're all doing in the game. Main thing is just have fun with it Most of us have only been here a week or two so we're all still getting to grips with things ourselves.
Best advice I can give is take things slowly and try to find a balance between getting coin and goods, build some military units and expand slowly don't rush this isn't a fast paced game very much a strategic game check the research paths as you go and don't feel you need to build each building as it becomes available and that includes military ones you'll find you can probably (at least in the preview) skip the horseman and catapult barracks entirely (obviously you should unlock then in research, but may not feel the need to use them). On the other hand I would suggest definitely building the spear men and slinger barracks (but that is personal taste). Take a read through the forum at your leisure you'll find some issues you'll come across and some helpful hints.
One last thing look at the research trees and see that you'll eventually need some products to unlock the research as you advance, might be worth building one or two products buildings when you can and remember if you don't have access to the resource (from your expanding empire) you can still produce products at a much lower rate 1 product = 4 hours and so on.
Mianly have fun and enjoy.