Where to go from here
By now, you should know the basics of Microsoft Cognitive Services, enough to get started with building your own applications.
A natural way forward is to play around with the different APIs. The APIs are continuously improved and worked upon. It is worth going through the API documentation, to keep up with changes and to learn more. In addition, Microsoft keeps adding new APIs to the services. Through the writing process of this book, I have seen three new APIs added. Those might be interesting to look into.
Another possibility is to build upon the smart-house application that we have started on. We have put down some groundwork, but there are still a lot of opportunities. Perhaps you can work on improving what we have already ...