like the others have said, promotion is great when you have something to promote! its like promoting a theme park, its better to promote it when there are tons of rides on it already compared to promoting it when it only has like, one or two rides.
more content is always great. but not too much as to some would believe. promoting your stuff when it has a hundred too many pages with be a demanding tasks for the reader sometimes, (in my perspective) so the best time to promote is when you're in the middle ground of things.
also, just being active and social is a good way to start promoting. continouous updates. interacting with fans, its the small things that get you an steady audience :3