capnvonbaron
Democratia gladii
2. Granary is usually very important!
Only in settler factories. Avoid them if your city is going to need an aquaduct.
4. Don't build spears, a handfull warriors can defend you quite easily, at a much cheaper price.
Kinda. Having thirty warriors numerically is as good as fifteen spears, but will cost a lot more to support. It is case dependant... but mostly I build spears until horses are available for attack units (warriors have a terribly short upgrade value in vanilla unless you're persian... in which case its still not great)