How the hell do people get resources so quickly?

I play as Britain, in every match I am outplayed by everyone, far less resources, and take long to build up. I don’t understand how everyone has so many resources and I don’t, I have 15 villagers usually by beginning of age 2, and get steamrolled before I can get past age 2 usually. Facing the computer on expert I don’t stand a chance they roll in with full armies and I barely have an economy yet. What am I doing wrong?