Why people wont buy my projects???

https://www.cgtrader.com/dusantrickovic this is my profile

You got only 300 views overall and already complaining why nobody buys your models? Man, you need a lot more patience when selling 3d models. A lot more. Especially when you aren't providing any wireframes nor description.

More pictures, more description, more everything.
Take a look at the top designers and try to learn from it.

wireframe missing + very simple quality of render for cars (interior architecture are good presentation and quality) .
No description

+ ( I am new on cgtrader but have some experience under the belt :) )
looking at demand/supply infographic arch interiors are in high competition category ( 14000+ models available..)
There's a bit less competiotion in cars niche but again, lots of good looking car models... you really have to make special offer/model to gain attention... Make an oldtimer that no one made before... and offer time limited discount... You'll attract attention for sure :)

At least I'd do it like that.

It's already been said but your biggest problem is the lack of pictures and description.

When uploading pictures of your model, the more you have the better it is, this gives your potential customers a chance to really see what you are selling. You want to ensure that the quality of the renders are also exceptionally high, you could have the best model of a phone but unless the render is sexy, no one will buy it. I recommend spending time learning the ways of which ever renderer you use. Among these screenshots you should contain Wireframes and UV maps so that the customer can see how good the topology is and whether the unwrap isn't a pile of garbage.

Your descriptions are also non-existent. This is not good! The description is the only way for you to talk directly to a potential customer viewing your product. You want to keep your descriptions detailed but short and to the point.

A general Layout would be:
Description: 2 to 4 sentences that explain what the scene is and potential uses for it.
Specification: A list of the important technical information about the mesh, Polygons, Vertices, Formats, Texture Resolutions, Shader Maps, Bones, Keyframes, Animation etc.

Here is an example of one of my products: https://www.cgtrader.com/3d-models/exterior/landscape/medieval-wooden-fort

You also need to Advertise yourself. Putting your meshes on the market place and waiting won't bring in much. There are 100's of Game Developer Facebook Groups which you can advertise on, Game & Artist forums, Twitter, the list goes on. Spread the word about your meshes and that will redirect traffic straight to you

The obvious answer to your question is: think like a customer. If you were browsing through the selection of car models and came across your Audi, would you buy it? Why?

Like other people are saying, the description is very important.
Does your car have any moving parts? Can the doors be opened? Can the tired rotate? Before you say "Yes, obviously", keep in mind that there are many car models that don't have separate parts defined for the doors or tires.
And how are the materials defined? Will the user be able to easily change the tires or will changing the tire material also change the interior?
Do you include any texture maps? If so, what size?
Is the model UV mapped?

Personally, I'd rather buy the model with a description that talks about the model's parts than a model with photo-real images and a poor description. It's easy enough to recolor a model, but it's not as easy to separate the doors.

Lack of proper description is probably a major killer. If you aren't going to bother with proper descriptions, at least make them cheap so that people are willing to gamble.