The very best photos, including stock photos, are simple and convey a clear concept. The easier the idea of the image is to understand the more powerful it becomes. The last month or so I have tried to submit to Dreamstime photos with a clear concept. Here are a few recent images:
My experience is that concept images sell well. Some previous concept images that have sold for me in the past include:
The simplier and cleaner an image is, and the clearer the concept, the more likley the image will sell. Challenge yourself to capture a clear concept in your photos and your success will grow.