One of the "tricks" that I use to get razor sharp images is to get my flash duration as short as possible. Normally by getting the MT-2EX's flash heads close to the subject and using a diffuser that diffuses the light but blocks as little light as possible. IMHO macro is really a form of stop motion photography. Although this video has nothing to do with macro it is about using a short flash duration to freeze motion. Chase makes four points concerning freezing motion and all but the second one is relevant to shooting macro. The first point is to keep the ambient light to a minimum and you can do that just by shooting at life size or higher magnification while setting the camera to a high Fstop (F11) and a low ISO (100 is best). Take a shot without the flash and if you can see any part of the subject then there is a chance that the ambient light in the scene is going to be a problem. One work around is to set the flash to second curtain sync, so that the flash is the last light source that the camera records. If there is any motion blur freezing the scene right before the shutter closes with second curtain sync can help to hide it. Points three and four are pretty self explanatory:
Discussion on freezing motion.