Drawing smoother lines is a real challenge, for many of us! Here are a few quick tips for drawing smoother lines.
For smoother lines, try not to draw from your fingers and try to draw from your elbow or shoulder. This might require a change of grip.
Try ghosting the stroke in the air before you commit.
When practicing ovals, circles, and lines, go _fast._ You also want to do linear relatively fast.
If you’re doing it traditional, try using a lightbox so you don’t damage the sketch when doing line art. This way you can practice lining faster and smoother with a lot less stress.
Digitally, all you need is another layer. A lot of digital art programs also come with a brush stabilizer as well, which can be super useful. Krita and Photoshop have it built in.