I swear babe, this has never happened to me before.
Only it happens to everybody. And it's okay.
I wrote a dud the other week. I thought it was a real cool hard-science concept told in a compelling way. Turns out no one knew what the hell I was talking about or enjoyed how I told it. As one of my kinder critics put it, "I think you may be on to something here, but I have no idea what. It's terribly vague."
There several lessons to be learned from duds. The first is that it's terribly important to have honest and trustworthy beta readers to tell you when you have a dud. Often, duds just need a few tweaks to turn from a chump to a champ. Beta readers and workshops will help you find the flaws and help you fix them. Even my best written work is really a dud until I've had some outside perspective to shine the light on its weak spots. So, yea for beta readers!
The other lesson that can sometimes be harder to learn is when to walk away. Sometimes I'll write a "terribly vague" monstrosity that's beyond help. Some beasts should never be born and it's important to put a bullet in them before they escape the lab. That's okay too. From those bastard born disasters, we learn what doesn't work.
And if there is one more lesson to be gleaned from the dud, it's perseverance. A few weeks ago I realize I wrote a dud. Last week I learned another story won a short story contest and will be published. Failure makes us angry, hungry, driven. One success is fueled by a hundred flops. The real trick is to just keep going. Take the lessons to heart and then try harder the next time. Keep writing!