When to push and when to build?
Solution 1:
There are proven opening sequences for every faction/map. There are numerous videos on YouTube which I used as tutorials. It also varies if you are playing against computer or a real person.
Usually what I as American is try to claim half of the map and situationally harass deeper into his territory. For Brits I take 2/5 of the map and build some defenses and then advance.