Positive critique.
The first appears oof to me ... maybe it's my eyes but I can't find your focus point. Also the perspective is a little off. Many people shoot macros of flowers from the top. This one appears to be just above and at an angle. It might make a better photo if you shot from a non-classic angle (with this particular shot or twist your camera a little). Also if you are trying to put focus on the main flower then I would use a slightly higher DOF (or get it in focus). But not so much that it brings the other flowers in the background in focus. One way this can be done besides using a macro is to shoot it with a telephoto on a tripod and zoom in.
My comments on the second pic are relegated to the fact that the perspective of the picture makes it uninteresting for me. (I look at a lot of pictures).
The third, you nailed, the focus is off. But barring that it has some potential if you frame it just a little more to the right and put focus on that large drop.
With these types of macros it's interesting to realize what impact DOF can have on your photo. As a social experiment you should set up your macro lens and tripod (or set it up on a table in your house so it doesn't move) then take 3 pictures or 5 or whatever going to different aperture values. This not only familiarizes you with your lens but also shows you quite the impact from say f1.4 to f16.
I don't claim or purport to be a macro photographer. Occasionally I get on my side or stomach though
An example of a razor thin DOF, this is f2:
http://lifeinstill.zenfolio.com/p574492488/h1c0989b4#h1fdf0ae1An example of middle of the road aperture - this is f5:
http://lifeinstill.zenfolio.com/p574492488/h1c0989b4#h1c0989b4