I have discovered something lately that is making my life easier. I don't know whether I read about it somewhere before or if I've worked it out for myself. In any case, that's not important. What's important is: it works for me. So maybe it can work for you too?
I have a few "big" projects going on. By "big" I mean a book and an online course. (I have other ones, hence "few" and not "a couple" but these are the ones I'm tackling right now.) As well as that, I have other stuff going so there's a lot of leaving stuff half way through and picking it up again.
What I've found is that, if I don't finish the small unit of work I've started (say, a slide or a chapter) it's easier to pick up. Leaving the work half-way through is a bit of a bummer as I do gain a lot of satisfaction from feeling like I've Completed something, with a capital C. But what I have found is that, when it comes to getting started again, it's much easier to pick up where I left off, if this is in the middle of something.
There's no blank page. There's no having to think about what comes next. You don't even have to go through the psychological barrier of Starting something...
It's already there, you just need to slip in and carry on.