As a start I'll point you in the direction of Scott Thompson AKA macro junkie who also used to post some stunning macro images over on the old DCM site:
http://www.flickr.com/photos/hooked_on_macro/
http://macrojunkie.deviantart.com/
Not his site but a few more examples of his work:
http://www.biobees.com/forum/viewtopic.php?t=3239
Having pointed you in the direction of a true master of macro, which of course is a highly specialised form of photography, here's my own opinion for what it's worth. I doubt you'll find many macro shooters opting for an aperture of f/4.5 - the DOF is far too small especially in combination with a focal length of 100mm. Again, I'm no expect in the field of macro photography but I think you'll find that the most favoured choice of aperture is in the range of f/11 to f/16 with focus stacking also being very popular. Your chosen shutter speed of 1/100 sec is also on the slow side considering once again the focal length of 100mm. When looking at the shell of the ladybird there is obviously movement which of course could have been caused by heavy breathing on the part of the ladybird herself (doubtful as no partner in evidence) but more likely by movement of the camera. I agree with Matt when he points out that live view might have been helpful, although, unlike the 7D which allows for zooming into a particular area to check focus during live view, I'm not too sure that the 50D allows for this. A read of the handbook will obviously confirm this one way or the other. Use of mirror lock-up can also be of benefit when shooting macro as even the small movement of the camera as a result of the mirror moving during shutter release can make it's presence known in extreme close-up captures. For now I'd personally give this 'rocking action' technique a miss and concentrate more on the fundamentals of macro photography itself perhaps revisiting the idea as your experience increases. I trust this doesn't sound like a put-down as it's not meant to be, but I know that your venture into macro work is relatively new and I think that you might be concentrating a bit too much on the 'advanced' technicalities before getting the basics right. Again as Matt points out, a tripod would also have helped here although I realise that this may well have been an opportunist shot with either a tripod not being to hand or not available.
Finally, if macro really is an area that you would like to explore further and is of great interest then I would strongly advise sending Scott an email (details on his deviant art site) asking for details of any recommended reading. You'll also notice that the equipment that he uses isn't all that extensive although the mpe-65mm doesn't come cheap.
All that said, your image does have a certain appeal although it's difficult to say exactly what. Um.