Start at the end
Starting at the end seems like a bad idea, but it is an amazing way to overtly show progress in a lesson.
As a starter give the students the question you expect them to be able to answer at the end of the lesson, if they can answer it now you may need to find something else for them to do, but the students should not be able to answer the question, that’s what your lesson is about.
At the end of the lesson get them to answer in a different colour pen so you can see the progress that the student has made in the lesson. It should be as clear as day. They could not answer it, you taught them, they answered it.
You do not have to wait until the end of the lesson, some students might be able to answer it at the halfway point of the lesson, push them onto the extension work. This process is a great foundation for making fluid lessons that change based on the progression of the class.