DOES your design/drawing have measurements & detail included? It's time for the nitty-gritty details folks. You're getting to the stage where you'll be handing off your baby to someone else to build. You must must MUST ensure that you including all the measurements, details, etc.. for your pattern maker to create your idea
Make sure you have enough MATERIAL! Y'know when you're at a BBQ and you run out of plates? Pretty big drag, huh? Well that's nothing compared running out of materials when you're building a prototype. The one thing to bear in mind is that you'll probably need to make a few versions of the prototype so plan accordingly!!
Be prepared to make SEVERAL prototypes. Yep, I'm going to repeat the previous point. Prepare yourself for making MORE THAN ONE PROTOTYPE. That's the entire point right? To make your dream product into a reality... and it's probably not going to happen on the first pass. This is your opportunity to make magic, so produce as many as you need!
FINAL PRODUCT: MANUFACTURER-READY PRODUCT! Allow me to dust off an old classic, BLIZZAM! (It's a combination of 'Blammo' and 'Shazam', denoting fantastical excitment). You. Have. Made. Your. PRODUCT!! And that product is designed in such a way that you can bring it to a manufacturer (don't know any? We can help you with that) but this is now some type of serious, real-deal, big, 'B', Business!!!
So, take a breathe. Put your feet up. You made it over the first hurdle. And the ride is going to keep getting even crazier....