While I was surfing the web I stumbled upon this tutorial over here: [link]
It's simply A W E S O M E and quite encouraging
I will copy-paste the most important and helpful thing though, which is the following:
How do you build the confidence? Follow these tips:
-Practice! Simply draw arcing lines on a rough sheet of paper. Large ones that fill up the page. They don't go anywhere in particular, but it really helps loosen your arm up so that you're able to make those confident strokes. Just break out the sketchpad and have fun drawing lines everywhere!
-Draw lines slowly. This will improve your technique. You'll get more "squiggly" lines when you first learn how to do this, but over time, you'll get less and less squiggly.
-Draw lightly first. When drawing illustrations, drawing lightly will build confidence in your strokes (you can have a few line breaks when you're sketching). Then go over the lines with a slower, more refined single stroke.
-Draw with your whole arm instead of just your wrist. You'll get a much broader range of control and can draw much cleaner lines this way. It takes getting used to, but it's the best way to draw.