Step 1
Make note of the fabric's right side based on how it's displayed on the bolt in the fabric store. Unlike apparel fabrics that must be turned right side out for display, upholstery fabrics usually come with the right side facing out. Ask the sales associate to pin a piece of paper to the fabric's wrong side or to mark it with a tailor's pencil or chalk.
Step 2
Feel the fabric's surface. Typically, the right side feels smooth to the touch, or at least smoother than the wrong side. Lay the fabric on a table, turn up one corner and examine both sides for sheen -- the right side may appear shinier than the wrong side.
Step 3
Examine the edge of the fabric, commonly referred to as the selvage, especially on monochromatic fabrics without distinct right and wrong sides. Often, the wrong side of the selvage looks and feels rough, has less of a sheen than the right side selvage, meaning it looks dull, and shows a loose weave or other imperfections.
In some cases, you may be able to see and feel tiny holes along the selvage; these are made by the machine that holds the textile in place during manufacturing. Normally, the holes pucker up on the right side and feel smooth on the wrong side. Once you wash the fabric, however, these holes become invisible.