If you're having trouble getting images accepted due to "exposure", this blog just might help...
First, since your images live or die on the screen, consider getting a basic monitor calibration tool. It will help set your brightness, contrast, and color to the levels accepted as "correct" by people like the editors at dreamstime, and the people who are probably going to buy your photographs. The goal here is for you to work in the same "visual environment" as your customers. I've seen good monitor calibrators starting at about $70(US). They are easy to use and worth the price.
The next step is to learn how a "good" exposure of a your subject should look on screen. Download a comp that somewhat resembles your shot, open it in your photo editing program, and look at the histogram. (Set your histogram to display LUMINOSITY...) Now open YOUR image and look at it's histogram, and compare your image to the comp you have downloaded. Make some adjustments to your image's brightness and contrast based on how an "accepted" image looks. By the way, this is basically the way I was taught to print in the darkroom: compare what you're doing with YOUR image to a known "target" print...
Now it's time to move a little earlier in your work flow! Set up your camera next to your computer, take a picture, transfer the image to your computer, open that image in your editing program on your "calibrated" monitor, and DON'T MAKE ANY ADJUSTMENTS YET!!!
While the image is on your computer screen, open it up also on your camera's LCD screen. THIS IS THE IMPORTANT PART: Adjust your cameras LCD screen brightness until the image on your camera comes as close as possible to the image on your computer monitor! You won't be able to get a perfect match, but if you do this a few times that little LCD will be transformed from a novelty into a highly useful exposure tool. Also compare the histogram displayed by your camera to the one displayed by your photo editing program. You'll soon learn to snag the exposure YOU WANT in the field!
You will also be more confident of your exposures, which can allow more energy to go into creativity and enjoyment of the process.
