I think the ‘things’ you should be learning are very subjective.
To me, it’s important that I’m learning that which interests me most, because there are too many different subject areas to learn them all, and often, more than one way to do something. For example, Unity is fairly well adapted to let people who are comfortable with programming set up the GUI entirely with code, OR, you can use the editor’s canvas system to not write a single script and handle everything with some clever mouse clicks and function assignments.
If I were to advise a new programmer where to start, it would be with the basics, of course. There are free tutorials everywhere on how to create simple things, but we learn what we care about. That’s why I think it’s important to choose tutorials on how to create something that looks interesting to you. That said, set yourself up for success by choosing beginner projects first.
The Unity website has some very well done tutorials for all levels, and being familiar with many of these beginner tutorials will come in handy throughout your unity development “career.”
Full Unity Tutorial Services
Absolute Beginner tutorial starting point