This cartoon character was based on a retro sci-fi idea. I wanted to show a character with strong pose, expression and silhouette with 3D art. My goal was to complete the process in 3D with the open source software Blender. In Blender you can configure your shortcut keys and the interface layout to match any stage of the process. What I did first was to prepare my tools for the task I needed and save the layout with a name.
(The 3D character creation method doesn't depend on the software. So you will be able to reproduce the same with your favorite tool).
References and Concept
You will not achieve an appealing 3D character if you don't have good references with good bases in character design. Working in 3D takes a long time and you will forget elements that are key points during the process. It's very important to define your 2D concept art design. In this case I collected a bunch of references from the internet and also had a female alien concept that I liked (Fig.01a). Sometimes I'll do a quick 3D sculpt concept too, like the one shown in Fig.01b.

Fig. 01a
Tip: Come up with a good 2D character design before you start modeling. Sketches are always faster and easier to change than digital sculptures. It will be a lot less painful.
Modeling
I started by modeling the volume of the character. As I often do, I started with the head, and used simple polygon objects like a box. Then I divided the box with vertical and horizontal edges. In Blender I used the option To Sphere with the box (Spherify in 3ds Max), erased one side of my box and added a mirror modifier (Symmetry in 3ds Max) (Fig.02).
Tip: To sphere a mesh, select the elements (vertex, edges or faces) you want to affect in Edit mode, press Shift + Alt + S and drag your mouse out.
At this point, I didn't pay attention to details and just tried to define the main shape well. I continued with the geometry, adding more edge loops and pushing the vertexes and edges until I was happy with the entire body shape and the proportions. Having contrasting shapes is very important when it comes to character designer. I kept this in mind and also looked for good topology (Fig.03 – 04).

Fig. 03
Tip: The topology that can be used for animation can also be used to pose your character in a easier way.