Learn the buzzwords and lingo concerning scalability and what it means to scale up vs. out. This presentation should help put your head in "the cloud" and wet your appetite to learn more about scaling your apps and processes.
This presentation was originally given at the August 2013 meetup of the Seattle PHP User Group. It was updated and given at Desert Code Camp 2016. I recommend you also check out https://12factor.net/ for information complementary to this presentation.