When I first started querying, I kind of dreaded my bio at the closing of my query. I didn't have any credits, hadn't won any contests, nor could I put that I had a MFA in creative writing, or was working toward one.
Which, before I continue, let me say-- You don't need ANY of that. If you have a fabulous story with a stellar query that lends itself to an agent requesting material (and possibly offering rep), then that is all you need.
But for myself, I've found that having something to include in my bio helps to give me a boost of confidence before pressing send. Seeing those acceptances in black and white at the bottom of my query letter lets me know that I can do this, that someone has found merit in my work, and that I'm not a total hack (aren't we writers so lovely to ourselves?).
Besides taking less time than writing a novel, writing short stories and submitting them can help alleviate the tedium of the querying process. With short stories, the wait to find out whether you've been accepted is often much shorter, and it's fun to anticipate cover reveals and even work on edits, which can help you get a feel for the process.
If you're interested in submitting work to the short story market (as well as flash ficton, poetry or magazines), the below links are a few places that you can find calls for submissions:
What are your thoughts on writing credits and short stories (flash fiction, poetry, etc.)?