Quality garments are easy to spot - espcially for someone who "loves to sew". Seams are finished, no loose threads hanging off, zippers are even and completely encased, buttons have "undermounts" on the wrong side to stabilize and are securely attached, linings are hand-sewn (or partially), fabric "feels" luxurious and behaves appropriate to the garment style (does it drape or stand away from the body?) - etc. One of the first keys you will have that a garment is fine quality is some degree of hand-stitching. Fabric matters tremendously - you can buy cheap silk garments and beautiful polyester garments- natural fibers do not always denote expensive/high quality.
My recommendation to everyone - learn to sew - at least a little. You will learn a great deal about fiber content, how to care for garments, and the amount of time/work involved in creating a quality garment. It will help train your eye, plus give you a tremendous feeling of accomplishment. Not to mention the luxury of being able to create a garment in the exact color, size, style, pattern that YOU want. You may decide that making garments is not your thing - but you will have trained your eye and your hands to know what a quality garment consists of.