Please use proper image titles for your threads, instead of the "My image was rejected, why?" or "Need help for improvement" type of titles, as they are not very helpful in distinguishing one thread from another.
Also, don't just post an image and ask, "What do you think?" as that's not very informative. Tell us about what your artistic aspirations are, and how the image relates to your artistic goals. Describe you intentions for the image and how you think you have failed at conveying it, and what you need help with. If the image has a narrative, then tell us what the narrative/premise is, so we can assess whether you conveyed it effectively. Also, be clear about what purpose the image serves. Is it a concept art for an intellectual property? Is it a narrative illustration? Is it a matte painting? Is it fine art?
Below is a post I made in another thread that I think everyone posting in the WIP forums need to read:
A lot of times, people posting in the WIP section don't give any useful information at all. They simply post an image and say something vague about "feedback welcomed."
What would be much more helpful, is if the person actually talked about the image, what's he's struggling with and unhappy with, what his intentions are for the image, what it'll be used for, etc.
Here's a fictional example of what would be really helpful:
"Hi, here's my latest WIP. It's currently about 70% finished. The background is more or less done, but I'm really unhappy with the colors--it looks too cartoony to me. The figures in the foreground are still kind of sketchy, and the poses look too stiff to me. I tried using photo references but I can't seem to get the poses right. I've posted the reference photos below for you to see.
I'm not too sure about the composition--it feels boring, like I don't have a focal point.
This image is supposed to be for a story I wrote, and it's a dramatic scene where the protagonists are gearing up and getting ready to fight the final battle. I'd like it to feel cinematic, with moody lighting, but my lighting just looks flat and boring. I want them to look like they are solemn and apprehensive, but also determined. It's supposed to feel like the classic "quiet before the storm" where the climax of the story is about to take place."
If you provide that kind of helpful information about your WIP, it'll make it much easier for others to cater their critiques and comments to your needs.
With that said, I think it's also important to be realistic in your own self-awareness and expectations.
If the person's a beginner, then chances are, he's not going to get much replies, because there are so many things wrong with his work that the only kind of reply what would really help him, is the kind that advises him to simply buckle down and study the essential foundations of visual art such as composition, lighting/values, colors, perspective, anatomy/figure, etc, and stop trying to construct images on his own for the time being. There's no way to give a detailed feedback because EVERYTHING about the image is so wrong that it would basically be like giving the person an art crash-course, which would end up being a very, very long post.
Another thing I see a lot, is people dumping a lot of images into the thread and then simply asks for comments. Nobody has the time to give thorough critiques for so many images at once. If you're asking for a portfolio review for a specific job title, then that's a different story, but that's not what we usually see. What we see is just a bunch of images dumped into a thread and then "Comments, please." There's no mention of what goal of the artist is, if he's just a hobbyist or what kind of career he's aiming for, what he wants to improve on the most, what he thinks his weaknesses are, and so on.