To get some real critique on your images there are several photography forums out there, I use photography-forum.org and talkphotography.co.uk I have learned a great deal from these sites. Most guys on these sites are not full time togs but have a passion for photography and are willing to share any knowledge they have. You can see their recent photographs and ask them questions on how that effect was achieved.
Most importantly you can post images and get feedback, wonky horizons will be spotted, boost contrast will be advised along with any number ways to enhance your shot or you could be told amazing shot and be asked questions on what youve done. The imortant issue is these guys dont know you and will give you honest feedback most will be polite, one or two not so.