The most important thing to say is that it doesn't have to be 100% perfect, like an engineering component. There is a lot of 'give' in the base materials, so perfection is not necessary. The main purpose is to indicate the curvature of your scalp, and the shape of the area you want covered.
You are already wearing, so if you are just seeking to replicate the unit you already have, then it should be easy. But if you are making adjustments, I would add these 2 hints. First, if you have an area of weak thin hair around your existing system, its better to shave it off and extend your template slightly to cover it. It is easier to blend the system in if it is abutting healthy strong hair, as compared with weak thin hair. Second, once you get beyond your early 20's you should start to include a bit of recession into the hairline contour. It adds a lot of realism. A completely straight convex hairline looks fake once you leave those years behind. If you want a second opinion on your hairline contour PM a pic.
Don't forget to mark the front and back.
Hope this is useful
Noah