We don't use text books in our class, we make them. Each student is given a binder at the beginning of the year. The binder becomes a reference book for the students as they fill it up with the lessons they have completed. Many standard textbooks have become a diluted hodepdoge of information, hard for most students (and even myself) to decipher. This binder allows me to create a resource tailored to my students.
In a self-paced class, students need to have access to any lesson, at any time. Thus, I created an area at the back of my classroom where every lesson is printed out and organized sequentially for students to take whenever they are ready to move to the next lesson. This allows students to continually work at their own pace. It also changes the dynamic of the learning process - students are no longer passively given assignments by the teacher and are now actively choosing which assignments they want to do.
Students set weekly goals via Google Forms every Monday and reflect on if they meet these goals at the end of each week. This is a reflective process where students are asked questions that allow them to understand what factors contribute to their success or failure in the class. It also gives me a document I can refer to if I see students are consistently not meeting their own goals.
Many students fall behind the class pace as the school year progresses, so I build in time to the class schedule for students to catch up. Before or after a break or towards the end of a trimester I won't move the lesson pace forward, giving students the opportunity to get back on pace.