I have done a lot of study online and definitely agree that the most important thing is to create a timetable and stick to it - it is so easy to get behind and then it is extremely difficult to catch up again, especially later in the semester when assignments etc. are due.

I also found it helpful to over-estimate how long things would take (eg. I would leave 2 hours for a 1.5 hour lecture just in case something happened and I was distracted / technical issues / needing to pause and look things up in the text that I didn't understand). That way I was never rushed and if I was having a good day I would keep going on the next task using that time, finding that I had a 'bank' of time later in the semester for assignments or if I was having a really bad day and didn't get as much done.

On bad days I would still keep to the schedule though too - even if I only got through one chapter or 1/2 a lecture I still sat and did the work. That way I was still in the routine of working and felt that I had been able to accomplish something.

I think environment is a big thing too - somewhere without too many distractions where you have everything set up that you need. I would make sure I had all my equipment, a drink and a snack and devote myself to being in that space to study. I would turn my phone off, just have some soft music in the background and turn off the internet (unless I needed to look something up) to limit distractions. My partner knew that time was when I was studying and would only disrupt me for emergencies (and was also really good at calling me out if I stopped early!).

Studying by distance is definitely a challenge and you need to be able to be relatively motivated and manage your time well but it is possible