Personally, I prefer to paint stripes and patterns in oils. Mainly, because it is easier to clean-up the edges while the paint is wet. I paint the base or background color completely: shaded, highlighted and blended. I let this step dry. I then start painting the stripes. The first stripe is the key as it will be the "guide" for all of the others. If it is a horizontal stripe, I try to make it parallel to the edge of the garment. The second line or stripe is also important as it will establish the spacing between the lines. Once you have the first two done, the rest are fairly easy. A very important point is trying to figure out how the lines enter and exit creases and folds. I use a fairly large brush with a good point. I don't try to paint one continuous line unless there are no folds. Instead pick a natural starting point and end point for the segments of each line. You want to paint each of these segments in a single brushstroke. I typically use three tonal variations for the stripe color: a shadow, base and highlight. I do most of the painting with the shadow color and use the base and highlight colors in the appropriate areas. Sometimes after everything is dry the stripes may look too bold. A very thin wash of Raw or Burnt Umber will effectively integrate the stripes into the overall garment.
