How do you know if what you have written is any good?

There are several ways to tell if your writing is good or not:

• Your own opinion. If you are honest, you know whether this piece is the best you can do, or if it's a piece of hack.
• Your ears. Read the story out loud. Sometimes, you can pick up poorly written spots better when you hear them than when you read them - especially if you have been working hard to edit and your eyes are starting to get blurry!
• Your friends. Have an honest friend or relative read the story and tell you what they think. Pick someone who will tell you the truth instead of just saying, "it's great" when it's really not.
• A teacher or mentor. Have an expert read over your work and critique it.
• Send it in for publication. An editor or agent will be quick to tell you if it's any good!

You don't. And I'm sure a few of books I buy aren't half as good as some unpublished novels sitting at the bottom of people's draws.

But the first rule is to listen to your own judgement. Are you proud of it? If you picked it up at a bookstore would you want to keep reading?

Second rule- listen to other people's judgement. Okay, just because your mum stuck that half page of fantasy you wrote when you were six up on the fridge doesn't mean you can write, but it's a good start. Ask friends and family to give honest critiques, and maybe consider joining groups or posting snippets of your work online (I recommend fictionpress, but you have to post a reasonable amount to get a response and I know some people aren't comfortable with that.

Third rule- just do it. You've got nothing to lose by sending something off to a publisher. If they don't like it, oh well, try again. If they do, I guess you've got your answer.