Personally I think your images are great - but maybe the keywords are a bit of a problem? For example, your recent tulip shot is wonderful, yet you've missed the most obvious keywords (to me): Tulips and flowers. You only have 'tulip' and 'flower' singular in your keywords. DT does not automatically sort that out for you, you have to handle plurals as well as spelling variations (color, colour) on your own.
Of course, it doesn't help that there are a lot of similar images to yours, even though yours are well done...
On other images, you have dozens of images basically titled "Lake Nam". I would highly suggest trying to be more creative in the titles and descriptions. You need to create keywords/titles/descriptions that are not working against each other. If a buyer want a photo of Lake Nam, you have it covered - but what about mountain lake, or blue lake, winter lake, etc. Since you are exclusive, you have the...(More)
I always liked your portfolio and I got inspiration from your work. I agree with the post of Leesniderphotoimages . Working for Dt gave me great satisfaction. This means that I get from the office to continue to improve my photography.