I think the recommendations are just that. Maybe half the time they're useful, trust your instincts on things like builders.

I personally expand in phases, not continually. I try to get at minimum 3 cities as quickly as safely possible. YMMV barbarian wise. Once I hit 3 I fortify a little, explore a little and build a builder to get going on refinements. I tend to go for scientific victory just fyi. Then when the three are humming along and I have some surplus military I start on the next 3-4 cities. This depends on terrain of course and those pesky neighbors.

Trading annoys me as I think you'll come to see. The terms are lame and mostly the other leaders use it to build animosity towards you when you decline. The only good trades I ever get are when I've just destroyed them and waited 10 turns or so.