WHAT I DO!Consider incorporating additional plots or exploring secondary characters in greater depth. This can add complexity and richness to your story. Another approach is to delve into the thoughts and emotions of your main character, allowing readers to fully experience their internal journey.
Sometimes I always write the dialogue first, when I'm done I have like 1000 words of dialogue, of course I put who said it, how it was said blah blah blah. When I go back, I add the actions in that moment, the descriptions and plot, etc. It always works for me, especially if I'm writing a long chapter, when I'm all done with the chapter I should have 3000-4000 words. It may not work for everyone, but if it works for you that's amazing.