I'm new to this site. Just wanted to know if it is acceptable to post a photo and ask the users for suggestions, like for sharpness, color, contrast etc...?
If not, kindly suggest any such website.
See this: Can I use the site to get feedback on a photo?
Asking specific questions about how to improve an aspect of a photo are ok, but it's not on-top to just post a photo and ask for broad opinions and suggestions.
We've pretty well decided that general "What do you think about this photograph?" questions are too broad. (See Should Photo Critiques be allowed? and Can I use the site to get feedback on a photo?)
But, since this is ostensibly a photography site and not merely for camera-gear comparison or a replacement for reading the manuals, I'd really rather err on the side of tolerance for broad questions about specific photographs. I'm a lot more interested in that than another "16-92mm f/3.2 vs 14-87mm f/3.9 which to buy?" or "Is the Nicatax 9000 a good camera?". I'd certainly rather do a little bit of back and forth with the poster to improve photo critique questions than have another question asking how to calculate the distance to or size of an object given certain inputs.
However, with that said, the questions do need to be in a basic Q&A format, rather than just looking for comments. Pick an aspect that you aren't happy with in your photograph, and focus our attention on that. Otherwise, if you're perfectly happy with the photograph already and just hoping for +1s... there are plenty of other sites for that.