The most important thing is to have a good drawing tool. In the image with the car, I have tried most of the available ones, like the MDC Toolkit or Paint.net. With the MDC you use the mouse or a keyboard to place objects in place and then draw lines between them. For example:
The key to the toolbox is to place objects and draw lines between them, and then draw a path between the two objects, that is, a rectangle. This way you can draw a triangle and the back of the triangle becomes a cylinder.
Paint.net or Paint.io?
Paint.net is one of the most popular options and a good choice for beginners to learn by heart. Besides it being relatively easy to use it is also great for learning shapes.
The toolbox also includes brushes, which give you the ability to shape your drawing. Brushes allow you to create textures, colors and shapes which are more easily defined for all objects. With brushes you can draw a rectangle, a circle or even something else you think up. I usually use brushes as a last resort, and sometimes they can also confuse beginners with their complicated brush choices. But as you gain experience you will learn better and can choose a better tool. There are more than a handful of brushes there available, if that makes one feel better about painting.
But when should I start using MDC?
Now that you know which tools work best for you, you need to select the right tool for the job. You should start with the brush tool, so you can see what objects you can use this tool for and what effect it will have on your image.
It will also be helpful to draw the back of your car or any other object you need to draw quickly and accurately. This will help you avoid accidentally creating artifacts and other effects that can make you lose focus on the task at hand.
Once you have selected the brush tool, it’s time to learn a few keystrokes and learn how to control it to give you the best results.
This can make the life of more novice users a little more complicated, as you might get confused and lose track of what buttons to press when. A simple answer to this is to keep using your mouse or keyboard until you’re comfortable with it. But, it takes experience and an increased level of intuition to use MDC as well.
As a first step, I advise you to try out