My advice is to take some of the pressure off by filling a prompt that is either from Prompt Post #1 or one that already has a fill.

---if you chose Prompt Post #1 whoever posted it probably has given up hoping someone will fill it, this takes some of the pressure off of you worrying you're messing up their chance to get a 'good fill'

---if you chose to fill something that already has a fill, your story will be an unexpected bonus

& you can always find a beta to edit it for you/give you encouragement if you need it