The quality of apparel can be distinguished by three factors: fabric type, construction, and dimensional stability.
Look inside the garment for quality. On better garments, you will see double-needle hems and two rows of stitching sewn parallel to each other.
Look at the shirt's neck and shoulders and you will find an inch of fabric sewn over the inside seams. Taped neck seams, taped shoulder seams and double needle hems secure the seams, help the garment maintain its shape and give a more finished appearance.