The age-old way of creating art concepts involves sketching on paper with a pencil of some kind. The paper-and-pencil method has its pluses. It can help your coordination and give you a clearer perspective during creation.
However, we can’t ignore the current shift to digital methods and the many possibilities it presents to artists. Drawing on a computer means a machine is helping you do a chunk of the work. Therefore, it can improve your speed, quality, and overall results.
Today, there are many free and paid digital programs that artists can use to do preliminary sketches and concepts. Examples of the more popular are Photoshop, Gimp, and Krita. In this article, we will specifically focus on Inkscape.
Inkscape
Inkscape is a free vector graphic manipulation program. It runs on Windows, Mac, and Linux computers. Besides being free, the program is powerful and flexible enough for those who want to push creativity to the max.

Typically, creators use Inkscape to generate and edit Scalable Vector Graphics (SVG). The program renders primitive vector shapes such as polygons, rectangles, ellipses, paths, and text. You can fill shapes with colors, gradients, and patterns; edit their borders, and adjust transparency as you wish. Shapes can be moved, rotated, scaled, or skewed to achieve the desired results.
There are many more things you can do with Inkscape. Here is a cheat sheet of essential tools and their Hotkey shortcuts.

Creating a concept artwork using SVGs obviously sounds insane, especially for artists who want to produce complex artworks with hundreds of elements. Still, visualizing the final work through a small set of colors can help you generate a solid structure of the final artistic elements. I like Inkscape because the program allows you to fine-tune individual shapes whenever you want without ruining other elements.
Example
The following image presents a simple art concept I designed using Inkscape. The basic idea is to have a hovering bird with a scanner strapped on its back and a bunch of rays probing some eggs. The entire concept was made by drawing, scaling, positioning, and coloring a group of SVGs. Though it took some time to finish (approx. 2 hours), the final result was somewhat pleasing and even gave me the confidence to try ‘concepting’ with SVGs again.

Here is a time-lapse of the entire project.