Question: How do I create realistic, but memorable tags?Answer:
If you were to spend some time in a public place - a market perhaps, or mall, or train station - paying close attention to the people who go by, you will notice that just about everyone has features that distinguish them. Admittedly, some are more distinct than others. But human beings are a pretty diverse group. There's a lot more that sets us apart than height and hair colour.
Try doing some people watching, and you'll see what I mean. Even better, as you're watching, be on the look out for anyone who looks like they could be in your book. Take note of their distinguishing traits.
Often, you only need a few good tags for minor characters, maybe a few more for major characters.