I asked the same question recently, maybe the answers are useful to you too!
I would recommend going through Beginner and Rapid learning paths on Academy, but also applying this knowledge in building out your own apps or taking a pre-built app from Marketplace and modifying it to your own requirements. The academy training is great theory but you really start to learn and expand your skills when you start building apps for yourself without following a step by step guide.
Hello Eline and Steve,
Both of your answers are appreciated and useful!
Thank you :)