Sketching is a common technique used to visualize your ideas and help you think about them. It forces you to transform the abstract idea present in your mind into a more concrete and tangible form that captures its essence. This process helps you to consider how your solution may be used by your target users and whether it fulfills the different design goals.
Pen and paper are the most commonly used tools for sketching. The simplicity of these tools is ideal to focus on capturing your ideas and iterating them quickly. They also represent a very low entry barrier to the sketching process. You can sketch anywhere, alone or with other people.
Sketch by Jack Dorsey capturing his initial ideas for a micro-blogging service named stat.us, which later became Twitter (source: https://www.flickr.com/photos/jackdorsey/182613360/)
Sketching takes advantage...