Fabric
Note the fabric. Branded clothing is manufactured from high quality, expensive fabric, pleasant to the touch.
Elements
It is very important to pay attention to elements, especially on accessories. Buttons should blend in color with the fabric. Zippers should also harmonize with the clothes and be as invisible, unless the opposite effect is a design idea.
Seams
This is the first indicator of quality clothing. Seams shouldn't crease or pulling fabric. This applies to the lining. Edge of clothing should be neatly trimmed by overlock. The quality of clothing and its durability is very dependent on the quality of tailoring. Expensive brands shouldn't allow themselves uneven seams and other holes that indicate bad quality clothes.
Lining
It good determines quality of bought clothing. Expensive brands use only silk or silk taffeta. This fabric is hypoallergenic, pleasant to the touch, and moreover it gives no extra visual effects. Lining shouldn't be visible.
Pockets
Don't be surprised. Pockets are also a good indicator of the quality of clothing. Firstly, lining on the pockets tend to be silk. Secondly, the pocket to be profound.
Labels
It is thought that the label on clothing is a guarantee of quality. Logically, the workmanship, unique fabric and good tailoring are hidden behind the highest price. Labels not less helps the customer to navigate. Obviously, the Celine bag will look more subdued than, say, a bag from Versace. Even so, remember that bad taste is often hidden behind a large number of labels. I recommend not to abuse the famous names and create your own personal style.