Keep your head down in neutral position with your chin slightly tucked during the roll. This will help protect your lower back and neck.
Avoid arching your lower back as you roll out. You can tell if this is happening if you begin to feel a slight pinching in your lower back. This can be avoided by shortening your roll and/or doing the roll on your knees while pulling in your lower abs.
keeping a proper form is important. The goal is to activate the core. But when done incorrectly, the ab wheel can put stress and strain on your back and hip flexors.
This exercise puts stress on your lower back, It is better not to do it if you suffer from lower back problems.
As you get more advanced you can do this exercise from the plank position - standing on your toes, and not using your knees. Later you can start the exercise while standing up.
This exercise might be hard for beginners, only extend the wheel to the point where you can control it, even if it is not much, with some practice, you'll get better and better.