You stay motivated and you have a positive mindset. There is no one or anything that can help . Except you and your mindset!!
I’m an author, so I know the struggle! For me, I take periodic breaks to make a cup of tea, or go to the bathroom, or do some menial task, and take a lap around the room on my way back. Even a few extra steps helps!
I have a sedentary lifestyle too. In that case a morning routine or even evening routine will help you great deal. By staying commited that you’ll exercise at a particular time you increase your chances of doing it.