Always finish the projects you've started. That's a firm rule. Do not stop until you've reached the end, or you will never get anything finished.
Also, hang out with authors, agents, publishers etc on social media. You'll get lots of industry tips and you'll also be in the right place to hear of any submissions calls as soon as they're made.
If you have something that might fit a submissions call, submit it. Don't wait until you think you're perfect, because that might be never. Get your stuff out there and keep putting it out there until it sells. Meanwhile, write the next thing.