First, find a publisher that does take submissions
Ensure your work will fit with what they publish. Read their submission guidelines thoroughly but don’t apply immediately. Find out what they want and then take the time to do a bit of research on the process.
Do send exactly what the company asks for and nothing extra. The main advice is to be as direct and compelling in your pitch as you can be. And short, max 2 pages 🙂
This Man This Pete