Tip #1) The Rule of thirds
For best composition, try to line up objects in your image according to 4 invisible lines. Divide the image into 3 vertical sections and 3 horizontal to find these lines. Now, if you try to do that with my image, it won't work because I cropped it down to screen resolution. The original does adhere to this.
Tip #2) Avoid brights around the edges
If you have bright sections next to the border of your image, it will draw your eye away from the main subject. This tip was passed from Ansel Adams to a great instructor I had and now from me to you.ORIGINALEDITED
Tip #3) Depth of field
Depth of field is important especially for macro photography. You need to highlight what your viewer should see and place emphasis on subjects in your image. The way to control this is to change the iris size. The smaller the iris, the sharper and longer the depth of field. This is done through f-stops, and the larger the number (22) the smaller the iris.
Tip #4) Feel the curves
Pure white should be avoided. A printer can not print pure white and our eyes perceive this as a loss of information. With a white point around 95% of full, we still see it as white, but information is still there which make the image more pleasing to look at.
If you are working in 16-bit images, but may convert them to 8-but later, use curves to select the blackest black and whitest white of your photograph. This calibrates the image to use the full gamut spectrum before you convert and loose information. "But that makes my image look fake!" you say? Use an adjustment layer to restore settings if you like. What this does is protect you if you work in 8-bit with photoshop 7 like me and minimized combing effects.
There are perfectly good exceptions to all of these in the name of art so experiment with some images. I'm in LA right now, but I'll try to post some before and after images of another photo I did when I can.