Oddly, for a tutorial, the answer is "do it again".
This turns out to be high value for the time. You can write the code fairly quickly the second time through; error messages have more meaning and context; and you will pay attention to secondary characteristics including performance and testability. Also, you start to internalize the choices of syntax or library design the second time around.
Just because you got to the end of a tutorial, does not mean you are done.