Let's get something straight right here and now. Describing your characters is about as various as the characters themselves. What I mean is that everyone describes characters differently, but I believe writers, especially young writers, get caught up in the need to paint an accurate description of a character. This need comes from a false necessity, and I'll be honest, I got caught up in it too.
In my novel, I finished my first draft and after a couple of my colleagues and friends read it, some complained (only slightly) about not knowing what the characters looked like. I agreed. I had not spent much time at all creating facial features for my characters. I had created body features—fat, thin, nice legs, strong build, but that was about it.
NO NEED TO OVERKILL THE DESCRIPTIONS
It was good advice and I went into my book and added more descriptions. I focused on eye color, hair color, facial hair, noses, and the like. These characters could be picked out of a lineup under a row of broken lights, if need be. That's how freaking precise I made their features. Now that I look back at it, I feel I overkilled a few of them. And then I looked even further back and realized I don't remember hardly any of the characters' faces and builds in the stories I've read. I don't remember what the characters looked like in my favorite books. I have an idea, but I didn't need the story to become a picture book in order for me to get an idea of what they looked like. I like descriptive writing. I appreciate how F. Scott Fitzgerald paints a serene setting—two whole paragraphs to describe a lake. But that's not me and, perhaps, that's not you.
GIVE A TRAIT THAT STANDS OUT
Yes. Paint a picture. Describe your characters. But don't get so wrapped up in the idea that you have to turn your novel into a scrapbook of detailed characters. You know what they look like, just give us a little hint. As my father always said about people offering advice, "Take it with a grain of salt." In other words, don't take it too seriously, but never shrug it off as nothing. One thing I did do, before and after getting that advice, was add little standout descriptions. Not just "her eyes were as blue as the heavens" (by the way, I would never write that), but something that stands out. One of my characters had a missing incisor tooth, another had a slight scar under her eye, another had a missing eyebrow. They're little things that make a character a little more interesting. A bushy beard or a slight limp is another way. Not everyone has to have something like that, but throwing one in there is always for good measure. Keep in mind that measure is good, so do it. (Or don't.) In the end, however, you could write the best character descriptions, but what will always stand out the most is not what is on the outside of the character, but what you put on the inside. A good story covers a book full of sins.