I think it is great that you are writing these tutorials and posting the code. Also the fact that you let people see your mistakes along the way is awesome; too many people are afraid to make mistakes in front of others.
First suggestion is for
As much as I would personally avoid that, if you want to go that route then I would suggest instead using generate and test.
Here are two examples of answers I have given related to the 8-queens problem that both rely on generate and test.
a. Understanding CLP(FD) Prolog code of N-queens problem
b. Hints to understand splendid program to solve Queens
The next suggestion is to add pictures. As much as they are hard to create, and also hard to get posted into certain sites, pictures can take a good tutorial and make it great. Remember beginners reading these tutorials will have a hard time just keeping the abstract concepts in their head, adding a picture will help to simplify many of the thoughts in their head, and also act as an anchor point for referring back to and validating if they are imagining the concept correctly. e.g Syntax diagram, Unification