I think I was supposed to fill in my particular [whatever it is that prevents/stops your writing], but I don't think I have a specific Achilles heel that way. Not that I don't encounter obstacles to getting my words in every day! There are multitudes of those things, from Stupidly Trivial to Truly Important. When I was a newbie writer, even the Stupidly Trivial stuff won all the time. These days, only the Truly Important stuff gets in the way of writing, and even then I bounce back quickly, all because of my secret weapon.
My secret weapon is: my writing habit.
I'm a huge fan of building a writing habit. Because I've spent the last twenty years developing a writing habit, it's so refined now, so solidly at the center of my daily life, that writing almost happens of its own accord.
Sometimes, sure, I have to fight the megrims, the tooth-pulling days, the sheer don'-wannas - but the writing habit has me at my desk, writing anyway. Even if I take a deliberate sick or vacation day, I feel weird not writing, because the habit is tugging at me. I feel like something is missing until I get back to it.
Human beings are creatures of habit - both good and bad. Habit takes over when we're not deliberately working against it. We all have bad habits we'd like to kick - and know from experience how freaking hard that is to do! Why not take advantage of this force of nature and our deepest selves, and build a good habit that's hard to break?
Building a solid writing habit is the best thing I ever did, which is why I emphasize it in my Author Coaching Services.
But you can do it on your own! Find a time when you can write at the same time, every day, even if for only five minutes. Or one. I know it's super hard to carve out that time. When I started doing this, the only time I could find was at 5am - and I am NOT a morning person. But I wanted to build a writing habit more than I hated getting up so early. If you absolutely CANNOT find a consistent time slot, then hinge it off something else that is consistent: like lunch hour at the day job, or when you get home from work, or right after you put the kids to bed. The most important aspect is that consistency, because that's what builds the habit.
Do this for 30 days - because that's how long it takes to build a habit - and keep doing it. After that, you can move it around without breaking it. It can adapt and change over the years - and it will take on a life of its own. It will feed you instead of you feeding it.
Seriously, the best thing for my writing I ever did.