Draw several rows of little boxes on a sheet of paper with the aid of a pencil and ruler. With a pencil, practice drawing a variety of freehand lines in these boxes. Begin by drawing straight lines in the first box, on the top left of the sheet of paper. In the second box, draw lines with jagged edges. Continue to experiment by drawing lines with straight edges, but gradually mix up combinations. For instance, draw parallel lines, but in the gaps draw diagonal stripes. Then move on to draw curved and circular lines only. Finish the exercise by drawing both circular and straight lines together.
Create as many different objects, using line art, as you can. As with all art, the more different types of line art you create, the better your all-round ability will become. Begin by using the tools you are most comfortable with. For most artists, this will be a pencil, then a brush. When using pen and ink for the first time, concentrate on simple drawings first. These simple drawings should be of a single object, but the subject matter should still be varied.
Use points of reference to make creating line art easier. This method should be used for long, straight lines, such as in a column. Before drawing a long, vertical column, put four dots in place as a guide. Two dots should be placed where the top of the column is, on its left and right side, and two dots should be placed where the bottom of the column is, on its left and right side. Drawing the basic structure of the column will then involve connecting the dots. For line art being created with pen and ink, or with a paintbrush, accurately establishing the reference points is more necessary than when using a pencil and eraser.
Try and create drawings with a combination of lines. These will look more interesting, visually. Subject matter for line art is unlimited, and the starkness of using lines only has some advantages over other forms of art. A portrait using the line art technique will bring out the features of a person's face in a prominent way. This will not be possible with more subtle art techniques, and not in a pencil sketch or watercolor painting.