Starting some bigger sites?

Good day , i though i would probably start few bigger sites whilst getting these mini sites ranking since i think i enough places to get links for them and trying out few more soon. So id like to have something to work on. So i though creating Adsense sites or Cpa (well see ) with 20-30 articles on them and trying to rank for good keyword and i bet the articles will rank for related keywords too. i was wonderin should i put all the content on sites at same time or few at time. Also is this even good plan at start
Thnx