I think inspiration is dreaming whilst awake. There’s no other explanation for the way the ideas leap between nuances of meaning and plot the way they do. It also explains the way that things can seem utterly silly once that inspiration leaves.
That being the case, I often feel like if I can hold onto the atmosphere and emotion of a thing, rather than the intricacies of it, then it stays for much longer. To keep it is to perfect the art of dreaming the same thing over and over again.
And, since I write fanfiction, I often find once the original inspiration has struck and you’ve begun writing, you need more than inspiration then. You need to a strike a balance between many closely related things. Inspiration is one, motivation, dedication, impetus, fanaticism and total immersion in the source material are the others. Get it right, and the story will flow like water. And if you’re posting, feedback (and lack of it) is a blessing and a curse. Feedback will buoy you up, but it can also interfere with your ideas. Lack of feedback can make you give up completely, unless the muse is particularly insistent.