Ed you like to ask the easy ones don't you? First of all I'd say that a flower macro is different than a flower close up.
Close ups: Like someone said above a close up is like a portrait. Make me see WHY you clicked the shutter. It can be any number of things, elegant shape, interesting interplay of light and shadow, dramatic color, beautiful back lighting, juxtaposition of different colors. What made you want to take the photo? Maybe there is one flower sticking above a bunch of others of the same kind, isolate it by using a narrow DOF so it really STICKS OUT. Maybe you've got two very different flowers close together, use a wide DOF to SHOW THE CONTRASTING SHAPE/COLOR. Sometimes I like to walk around a flower if I can to see how the light hits it from a different angle, a ho-hum flower in direct light might make a great shot if it's backlit and vice versa. Like this shot, nice pretty little blue flower but seen from the front, and directly lit, kinda ho hum, but from behind and backlit a much better photograph
Also pay attention to shape, some of the larger flowers have distinctly different shapes in profile vs head on. This lily would have made a nice shot head on, but it's much more effective in profile, just because of the shape. BTW this shot would have been a lot better if I had narrowed the DOF down, but I was just starting out with flower photography at the time, I would do it differently now.
If I can get someone else to see what I saw, what made me want to take the shot this particular way, then I feel I've made a good photograph.
I approach flower macros differently. For me, a flower macro is about DOF. What did I leave in focus and what did I leave out of focus. Many times I have no idea what exactly I will see when I focus closely. Remember the Flower Macro monthly challenge? I just loved the shot that looked like a wizard in a cowl with his nose sticking out. I personally doubt the photographer saw that before they looked thru the viewfinder, but the super thin DOF bought it out. In this shot I was planning on focusing in on the opening of the bud with all the little pink threads curled up in there. But the exterior proved to be more interesting to me with the sharp needle like thorns and the spider web like covering underneath them.
What I'm saying is keep an open mind when doing macros and vary your focus a bit, you might be surprised at what you see.
I've got literally hundreds and hundreds of flower shots here:
saltwater's photos- powered by SmugMug
Some are better than others, but it might give you some ideas.
NaCl(hope that helps)H2O