How do I learn to build machine learning apps at scale? • /r/MachineLearning

Over the last year, in my spare time, I've built several small machine learning apps. For example, one that predicts the San Francisco fog at a neighborhood by neighborhood level. I have ideas for other things that I want to build, but at a much larger scale, for example large recommendation systems off Twitter's API. I've tried looking for tutorials or courses on how to build scalable machine learning apps, but I feel like I'm drowning in a lot of stuff I don't understand -- distributed architecture, MapReduce, Spark to name a few. Suggestions for the best way for a beginner to scale to get started?