Inking in a Sketch on paper
This is a before and after the inking of a sketch. The character is from a comic I am currently working on and I wanted to try drawing it traditionally before I worked on it digitally. The Sketch is actually scanned into the computer with a scanner and copied in case you need to start again as ink is permanent. Usually if you want to make major changes to a sketch, using whiteout and copying it is usually what artists do. For this particular scetch I would opt to redo the whole drawing as the umbrella size and pose is off.
Tips for getting started
Inking is simple even it you don't have copier on hand! Just get a piece of paper and a pencil and sketch something, whether is drawn light or dark doesn't matter, though a light sketch would be better for defining your line art more. Once you finish your sketch, Draw over it once again but try to draw keeping your pen on the paper as much as possible. Inking both defines the shapes of your subject and de-emphasizes aspects that aren't essential to the drawing. You may see that some parts in the inked sketch are darkened with cross hatching and filling in, you can do that as well or you can simply focus on getting the shapes correctly. A tip I came across was to make the lines thicker on the bottom, that way, if you color it or not, it has the effect of a lightsource!