I find it so extremely hard to be persistent in preparation for the ACT, and it’s due to lack of motivation.
Is there anything you do help stay focused? Please send me some words of advice. I could use some inspiration 
Picture yourself at your dream college all made possible by your solid ACT score. Now picture yourself at all the other options that admit lower ACT scores. Hope that image helps! The other motivation I share with my D is the sooner she attains her the goal, the sooner she is done with testing. Good luck, prep, and you will do fine.
Motivation is temporary, used to get you started on a journey. You need discipline…the drive to finish the journey. Many people are helped by making a study plan and scheduling it on your calendar. Maybe your plan is to prep for the ACT 30 mins a day. View that 30 mins as an investment in you…you’re the only person that’s gonna be able to make that investment, you’re the only person that’s gonna care. So decide to treat it as a priority in your life. Everything else goes on hold for that 30 mins. You’d be surprised how quickly it can become a habit! Good luck!