Make a list of ten ideas for how-to guides/articles/posts you could definitely, absolutely write. List more if you get on a roll. It doesn’t have to be a list of professional things; it can be a mish-mash of all kinds of things you know you know how to do.
Maybe it’s a straightforward how-to about a task you know how to do. Maybe it answers a question you get asked all the time. Maybe it’s something that feels funny or awkward to even be in how-to guide form at all. So what? Just list what comes up.
Note the ones that feel exciting. Note the ones your work or life credentials would bolster. See if there is overlap. Write that one first. Save the others to your ideas file.