As I described in a previous post, simple stitches in crochet worked in stripes of different colors can produce many pleasing, and often complicated-looking results.
By having many colors going at the same time can prevent the eye from detecting a regular pattern. So it is easy to work in new colors a old ones run out, producing a gradual, shaded effect.
Conversely, one can also create an obviously and intentionally striped effect.
A combination of stitches may also be used to increase the illusion of fairisle. For example, interrupting stripes of (sc1, ch1) with a row of double crochet can be very pleasing and improve the drape of the fabric.
One may also create vertical stripes using (sc1, ch1). When working in the round, verticle stripes will result if the single crochets are worked around the chains of the previous round. You use two colors and change them every round.