Hah, thanks. You're sounding a lot like me when I started. I saw Niels working on a bunch of stuff and decided to download some mods of cars I liked and started trying to improve them, back in the days of rFactor.
I think that's a pretty good start. Learn how to do research first and how to read data and put in all the simple things correctly first. Then over time you'll read more and try more and figure out suspension, aero, tires etc.
It took really long for me to start producing anything of value, even when I was reading books and looking at cars made by the pro studios and good modders. I think nowadays it's easier to get started; find a car to make, run into a big problem then come on CSP Discord mod-talk channel and post about it. Someone will help. I didn't have anyone to help early on; so my stuff also was trash.
Right now just start figuring out basic mechanics like how springs work, how dampers work, how levers work. You'll make a lot of cars without knowing how basic things really work in the sim and IRL. That's ok, but the sooner you do, the sooner you will have the tools and confidence to approach problems in a purposeful way.
I don't think my methods are so complex or my work so good. I don't even have my own spreadsheet for most things, I just use available tools and document most my stuff in notepad. But I'm alright at the process of *making* the car. Nowadays when I have people who just do the research for me on most of the car, I can put out a new one fast. It just takes long for it to become more solid, because you can't always find or understand all of the data on the first pass.
I've only ever heard that I don't know what I'm doing, or my stuff has more mistakes than other people's and that's why I have to update so often, so I'm pretty surprised a newbie sees it the other way round. It's not *entirely* untrue for some cases, but honestly it just means that when my car has problems, I fix them. They don't remain like on 90%+ of mods which start out bad and never improve.
Of course the best way is to just do it right on the first pass, and for some cars I had so much data that there's not much to improve over time.
About professionals' cars, like Kunos and other studios. I will say it right here that most my cars are more accurate and better made than any roadcars made by studios.
Part of it is because sometimes I know better (What were they thinking when making the E30 and Yellowbird rear? Why does the MX5 NA not hit the bumpstops when everyone knows it does? Why does the FD have artificially strong springs?) but honestly often it's because they have anywhere from a day to maybe a week to work on a car. They don't really get any special data like everyone is saying, so it's mostly the same process. Some of my cars are alright after such a short time if I have good data, but what about the ones which don't? You get version 2.0+ after 6 months. Pros don't have that privilege and they must simply move on. It's one of the benefits of being a modder; you don't get paid, but you can do what you want, as good as you want.