For the collab/partner part, keep trying but be OK if nothing happens because that's not really something you can control. Everyone works differently so it might take a while to someone that fits.
Putting up your shorter works lets the artist see a bit of what they will be working with, so they can decide if they would like to work with you. If artists are typically expected to show their work, it makes sense for a writer to do so too. Check out the "Before Submitting your Collaboration Request" pinned at the top, and try again when you are ready.