I've been doing a lot of google searches of site:steemit.com something to dig around conversations that have happened since launch. There's a lot of good resources out there to help learn. I've also been watching and learning from a lot of the open source projects that have been happening and digging through their code.

Basically the technologies you'd have to learn are just querying a JSON-RPC API or Websocket, and then learning what all the API endpoints do.