Are you asking about "Making" (as in working with the metal yourself)
or, "Making" as in sitting with someone doing CAD rendering (or drawing) to your vision?
There is a huge difference, especially in the quality of design & finish work if you want a piece that fits your needs and looks "Pro".
1. you need a drawing /rough sketch / screen shots of the basic look you want.
2. You need to declare a budget AND what materials you want the rings made in.
3. You need to declare a timeline (due date)
4. you need an accurate ring size.
5. You need to state the size of the diamonds you've purchased , both in carats , and in millimeters.
6 You need to be prepared to post a deposit to start the process (generally 50 to 75% down on custom orders) (I know this will bring comments....).
What to expect.
1. Solid drawings / artwork that addresses your needs.
2. A fixed Quote that will only change if you change something
3. Communication, in some form, about the progress (will vary with the complexity of the project).
4. To pay in full at the completion of the project (unless otherwise agreed upon)
5. On time delivery.
These are the basics of ordering a custom made piece.
There are a number of people here that can do this work,
as well as putting the project up for review on the "CustomMade" website.
Best wishes on your dream ring,