This is a very helpful 32 minute video by magician
Ekaterina, who covers the whole journey required in producing a custom deck of playing cards, gleaned from her own experience with the production of her Fox Playing Cards:
https://www.youtube.com/watch?v=OJhrIAfWgdsOverview of contents:
Step 1: DESIGN
Think about what type of design or brand will be portrayed on your custom deck of cards. It's always better not to make it "too personal" so that more people can relate to the brand and buy into your design.
Step 2: PRODUCTION
Here are a few companies you can partner with to bring your project to life: USPCC, Cartamundi, Legends Playing Cards, Make Playing Cards (MPC), Hanson Chien Productions, Clove St Press (tuck box).
Step 3: GO TO MARKET
Think about how you are going to tell the world about your cards? Are you considering a Kickstarter campaign? If you don't have a big following, it's definitely an amazing platform for visibility. Think of every detail - domain names, instagram handles, etc
Step 4: FULFILLMENT
Final step - getting the cards in the hands of your loyal supporters. If you are considering partnering with a third party company, consider these two options: Art of Play, Gambler's Warehouse
INTERVIEWS
Learn from the experience of other creators. Features interview with Kier Gomes (creator of Slow Hands deck) and Derek Grimes (creator of the Paradigm deck).