This is the title of a talk I gave at my local meetup. You can find the slides on speakerdeck. It was basically a introduction to UDP, TCP, TLS and HTTP, to understand how they work and how to make your application load faster.
I explained a vast range of topic, from very basic (tcp handshake and the impact on latency) to more advanced (tls sessions tickets and session resumptions), and the feedback was pretty positive. I think everyone learnt something :)