Read something about how far your Pokemon is along it's arc before it evolves is where it will be when it evolves, which could mean a powered up first evolution will be on par with where a second evolution would be if you evolved first.

Best advice I saw was to not evolve any starter level Pokemon until you have enough candy to evolve it to the final stage. I've found that good suggestion as have definitely found more powerful Pidgeys and Ratattas than the first one I evolved.