I use YouTube and Twitter the most. I use Twitter because I’ve had it for a while, I wouldn’t recommend starting now if you haven’t, but posting things like screenshots, clips of dev footage (Good, bad, or funny), small rambles about the dev process works well in that setting.
YouTube is a much showier affair, and I do devlogs there, showing off “checkpoints” in development, or any major setbacks that could use addressing. As a solo dev, it also helps as a way for me to verbalize certain aspects of development and solve issues.