I’d suggest coming up with something you want to accomplish and follow a tutorial on how to do it in Python. Perhaps you want to learn networking? There are many tutorials for socket communication in Python. What if you’re into computer vision? How about you try to use scikit, numpy, and pandas to identify the areas of deforestation on a map by using before and after photos? The world is your oyster. I recommend buying a microcontroller or system on a chip as well, but that’s not required.