Perhaps go back & read over the story, looking for places where you know what a scene looks or feels like, but you kinda left the reader to imagine it for themselves or to just skip over those details.
That's not "padding" because it adds to the reader's experience, you're not just stuffing in words to hit a specific number.
I find I have to do that rereading & describing things, because I often go writing my way merrily through loads of dialog, all the while with a scene in my head (e.g., who's sitting, standing, what are they doing before or during the dialog, etc.) but I forget that the reader won't see any of what I did unless I tell them how to.