Been there, done that!
I did all my CPL groundschool, the higher of my two degrees, and most of the teaching theory for my CRI distance learning and also did my CPL flying part time. The last is the only bit I regret as I think doing the CPL flying full time somewhere with decent weather would have cost me a lot less.
As Richard says, different people work best at different times. For me it was generally about 2 evenings a week, and two 3-4 hour slots each weekend. If mornings work for you, use mornings.
The most important thing for me, for all of those, was having a plan - generally blu-tacked to my study wall, and forever being ticked off or amended. But, the plan was absolutely essential to time my progress, and to ensure that I was on track to achieve within the timeline I needed or wanted to work to. (In reality both my PhD, and my CPL groundschool took about a third longer in months than I'd hoped, but I still got there). Having lots of achievable targets within that plan was really helpful to my personal motivation. It also helped me pace myself, and avoid burnout through trying to do too much too early.
The next most important thing is the passion. I honestly think that if I ever stopped finding what I was doing interesting, then I'd have just given up. That takes a certain amount of self-persuasion.
Third, and for me least important is self-discipline. For me personally I can only keep doing stuff if it's interesting and worthwhile enough for me, and if I can't find that, I find it tough to separately find the discipline to do something I dislike. That said, I needed it for air law, which try as I might, I will never develop a passion for.
Obvious other things: having a working space and some dedicated shelf space are very good. Organising life to grab a few extra hours here and there helped a lot - for example I made a point of, where I could, travelling to meetings by train rather than car, as a long car journey is lost time, whilst a long train journey is uninterrupted free study time.
I don't know what your own educational background is TM, but I was also helped by good study skills from a good school and tough first degree. In particular I already knew the importance of active learning, developing my own notes, using multiple sources, and precis. If you don't have a strong study background, you might find that time now invested in learning good study skills will pay back with a lot of interest.