Look at it! Feel It! Does it feel thick and/or luxurious? What is the weight? If it’s summer wear, does it have a thick but lightweight feel (think a good quality silk) or does it feel itchy and flimsy? Look at the weave (the number of threads per square inch) in the fabric. Is it a large weave (cheap) or are the weaves dense (higher quality)? How do you check? Hold it up to the light. You shouldn’t be able to make out much behind the garment. Look at the label for the fabric content. 100% natural fiber fabrics are higher quality than synthetic blends. If it’s 100% cotton, it should be thick cotton. How do you check? As before, hold it up to the light. You shouldn’t be able to see right through it! If you have fallen in love with a garment that is a blend, use common sense. If you are holding a wool blend winter jacket that looks like it should be heavy and it’s not, it’s cheap fabric. The more expensive the fabric, the more care the manufacturer will take to make sure patterns and stripes line up perfectly. Another quick test to check the quality of the fabric is to grab a handful then let it go. It should return fairly close to it’s original shape.
One of the easiest and fastest tests is to look for loose threads and broken stitches. Seams should be tight, but not overly so where it would affect how the garment hangs. The more stitches the better. A double stitch is going to hold up much longer than a single stitch. Also, look at the stitches themselves. Are they straight or do they look like someone rammed them quickly through a sewing machine? Check the buttons/fasteners. Are they on securely or do they feel like you could easily pull them off? Does it have a zipper? How easily does the zipper move up and down? Is there any detailing? How is it attached? Does it look like someone glued it on or did they take the time to really sew or attach the detail? Grab the garment on both sides of a seam and pull. If it looks like the threads are pulling apart, put it back on the rack. Also, high quality garments never have raw edges or seams. Everything is finished so that there is no chance of unraveling. Also, larger hems at wrists and ankles mean the designer/manufacturer has left room for alterations. Is there a lining? Lining takes time and extra fabric. It should be of a quality of fabric that does it’s job. There’s no point in a flimsy see through lining in a white skirt since the whole point of the lining is to eliminate being able to see right through it!