There are few better ways to learn about mistakes in photography than watching someone knowledgeable critiquing photographs. This video is exactly that and contains seven mistakes that are easily avoided.
It can be difficult to be objective when it comes to your own photography and that isn't necessarily bad. I have spoken before about how some of my favorite shots of recent times break rules and don't fit neatly into familiar compositions, and I'm ok with that; if I enjoy the shot, who cares if you can't draw 6 squares over the top and circle intersections of the lines? However, there are times, particularly when you're newer to the craft, when you need to accept that more experienced photographers don't like certain aspects of your image.
The example that jumps to mind for me is the first shoot I ever did with a model. This "model" wasn't technically signed, but had been and was a perfect subject. I setup a shoot at a great location and we took a lot of shots that I liked. However, there was one I was really rather fond of and I believed it to be one of my best images. Some months later I entered it into a competition in which images get critiqued and it got shredded. Once I'd licked my wounds, I saw what they were saying and they were right. (For the record, it was overexposure. I thought I was shooting for high-key, but I'd missed the mark and lost texture.)
In this video, Nigel Danson — an expert landscape photographer — goes through some viewers' images and highlights what's good and what's not quite right about them. This is a tremendously valuable video to anyone looking to improve their landscape photography.