I agree with Bitter jeweler. I've given critiques on images that I presumed were from beginners, and with few exceptions, the advice (whether given by me or others) seems to disappear into thin air. Later postings from the same people, if they bother posting again, tend to be more of the same. So, at a certain point, you wonder, why bother, echoing what BJ said above. On the other hand, there are a few that have taken advice and have shown what they did with that advice. Subsequent images show movement, evolution. There is an incentive to help.
Part of learning anything, is to understand enough to ask the right question. Which implies that they know enough structure to determine what they don't know. Having beginners explain their thinking process allows the more experienced members to get a better idea of what the operating knowledge base is. For instance, if a person has "soft" images and doesn't understand the relation between DOF and aperture, then telling them that their focus placement left too much of the subject outside the DOF range, will sound like gobbility-gook. So in that case, you need to get them to take the baby steps, that will allow them to understand at least some of the elements that contribute to image sharpness.
I like Chris's (Manaheim) list as a starting point for a conversation. If some of us think we know better, then give the suggestions as to what can/should be improved. If we disagree, then that's fine too - disussion can often sharpen the issues and lead to better understanding. I've been on other forums where the critique process is quite elaborate and is monitored/moderated quite aggressively. However, the people receiving those critiques have, in general, excellent technique, and the discussion is usually over artistic or expressive decisions. Many of the first-time posters here are perhaps years away from that level of expertise. On the other hand, we do come across some beginners who have undeniable talent and have stunning images with very little prior experience. Those people can teach the "experienced" among us to "see" better. So, let's continue the conversation. And let's ask for posters to give us the reasons for their decisions, their images, and their comments. In many ways, those reasons are more illuminating than the decisions/images/comments themselves.