I recently wrote the following to a mechanical engineering student who was wondering how to develop practical electrical engineering skills, specifically in terms of electronic component selection, circuit design, and consumer product polish. While the following is an N=1 anecdote I do believe that this approach can work for many people and many fields as well.
Common wisdom says that teaching is one of the best ways to develop mastery of a topic. Why is this? It's the grapple - struggling to meet eye to eye with a student and molding your own understanding of the topic to their learning style.
When you just need to Slack from the command line: "Slacker" is a simple weekend project CLI interface to Slack. Slacker isn't a production-ready tool, but perhaps it will be one day. If you live in tmux or the command line like me, you might find this a fun, curious little project.
Full-text search, unlike most of the topics in this machine learning series, is a problem that most web developers have encountered at some point in their daily work. A client asks you to put a search field somewhere, and you write some SQL along the lines of
WHERE title LIKE %:query%. It's convincing at first, but then a few days later the client calls you and claims that "search is broken!"
The Botanist -- a long-term side project of mine -- is a 2D fantasy RPG intended for release on multiple platforms, including web, Android and iOS. The game features an immersive universe with deep supporting mythology and lore; a relative rarity among mobile games.