Erica, it might be tough at first, but it will help you improve your photography.
Before some other people come here and say that, and I know they will, concepts sells, just mark my words
So I wont focus on that, because somebody else will :), and tell you some technical stuff.
When you are shooting, look the whole viewfinder, every corner, before pressing the shutter button, its much easier to get rid of that extras that shouldnt be there when you are shooting (an arm, a head,...) than later in photoshop.
Before uploading, check for the basics, horizon aligned, dust spots, etc, get rid of what shouldnt be in the image with photoshop, garbage cans, dirty in the grass, whatever.
Think about what your image is about and find some ways to emphasize it, darken uninsteresting areas, unsharp them, balance the light between the sky and the grounds, all you can do to make your image spark.
If the image is unsharp, you might try to decrease resolution down to 3Mpixels, the minimum, if it is stil unsharp (check at 100%), dont upload it.
I hope this helps.
Canon EF 70-300mm IS/USM f/4-5.6
Canon 100mm f/2.8 USM/Macro