Here's what I believe:
There are three top level goals of visual art. They are goals because successful/popular images contain a healthy mix of these three concepts. I did not invent these concepts. They've all been written about by great thinkers and artists. Most of which I haven't read. This is an attempt to congeal these concepts into a belief system for myself. The following is not based on facts, research or science.
Contrast in an image gets you curious. Contrast is said to be the spice of life. This is because or brain rewards us for assimilating new patterns. New patterns are basically old patterns put together in a new way. That is what contrast is; something next to something dissimilar.
Contrast in images can be in color, lightness, saturation. Ctrl+U, You know... It can also be thematic or conceptual. Art books, teachers and tutorials seem to focus on the paint rather than the ideas. This is fine, it's their job. BUT the thematic or conceptual is what gets you from only professional to "WOW that is awesome!" At least in the realm of illustration...
I've done (and keep doing) tons of characters that are not complete failures in anatomy and proportion, but still quite boring for not showing anything new.
YOU NEED A PLAN FOR YOUR CONCEPTUAL CONTRAST.
Light make you believe. Light is a shortcut to the world outside of the picture. It is through light we perceive the world. When a picture lacks light, it turns into a schematic. Our brains recognize it as a representation of reality rather than us buying into it as a reality.
Light is very difficult to handle. Do not despair. You do not need to paint realistic light. What you need is believable light. It can be caricaturized. Many times that will be stronger than an accurate simulation of photon beams. No amount of 3D software will ever render a good image if it is not in the hands of an artist.
YOU NEED A PLAN FOR SHOWING LIGHT.
Emotion makes you grateful. Recognizing emotion in others is, thanks to evolution, a key part of successful pack life. The brain rewards us with funky chemical when we practice empathy. For many it serves as a short respite from our own emotions, which tend to be re-runs. Our own emotions may be more real, but all too often negative. Give me a break from the guilt and doubt of modern life and I will be grateful.
It is probably so that when you can convey our own emotions, you are a true artist. Personally I can't bring myself to try. I wouldn't know where to start. Fortunately you don't have to. You can get close enough by conveying the emotions of the characters in your picture. It's like acting. I've cried in front of a movie even though it's apparent that it's not the actors own emotions being conveyed. To get the best result, you should get in the mindset of that emotion and let it seep into the drawing. There's magic involved here. Thinking about emotions will not help that much. They should be felt. I'm starting to sound like Yoda. Never mind... I'm not the first one to say it.
Just a small message to the people in the modern art scene: Provoking disgust is not the same thing. It is a cheap trick. Stop promoting it. Enough with the close-ups of genitals already.
YOU NEED TO KNOW WHAT EMOTIONS YOU WANT TO CONVEY.
This sounds a lot like preaching. I'm sorry. It is preaching, but the intended audience is myself. It is supposed to be a mantra to help me start images with the right priorities in mind. If it helps me or anyone else in the fight against mediocrity, all the better. If it works, I'll reverse the order and call it "The ELC principle." I know elk is spelled with a K, but "The Moose principle" doesn't make any sense at all.