Some here will already know me as a patternmaker. I now do it for fun and to keep my hand in. If I don't do it for a few days my hands seize up!
Anyway. I can probably best do this by showing more than one model as I always have a few on the go at one time. So I might show information on an Autobianchi A112 rally car, but master making on a Piper GTA and finishing on a TR2. Whatever I show it will show the whole process right through to screwing the chassis in to the body after priming and painting.
I hope it all works out and is informative.
To start with, you need information, references. I start with a google images search to familiarise myself with the real vehicle. Here a first word of warning....you may find that modern restorations, done in the best intentions, are often far from accurate. Little changes to details, even shape, can be a common factor, so try to get period pictures if you can. Not only will they be bang on accurate, but they'll likely be black and white which will always be more contrasty and therefore clearer. You can now view a complete online archive of Motor Sport magazines and there are no greater references than these. If you can find drawings, great, but often either what you can get are obviously wrong or at best a bit doubtful. Check them against published wheelbase, track and overall dimensions. Check those from more than one source if you can. They can be wrongly quoted too.
I find the old source of vintage slot racer-online is good for all the drawings that appeared in the old Model Cars and Model Maker magazines of blessed memory .http://www.vsrnonline.com/VSRN_Main.html
A more modern source is https://www.the-blueprints.com/ which contains thousands of drawings. There are others. You will possibly find some more if you google the car name followed by "drawings" or "dimensions". Such a search will probably send you to the very useful resource of Conceptcarz or http://www.ultimatecarpage.com/ These last two will have lots of lovely colour pictures of largely modern restorations, so enjoy, but be careful.
Next, I'll be going into the process of doing drawings from photos, where no drawings are available.
Cheers,
Martin