I noticed pronounced shadowing in the bottom-right part of the image. Use a piece of white card-board, hold it close but just outside the frame to bring some light into that dark spot. Silver cookie sheet also works wonders.
Otherwise, close down f-stop, tripod, remote shutter (or use self-time), mirror lock-up (or use self-timer) as the others mentioned before.
Last but not least, take more pictures. I usually take about 20-50 images per specimen, just go give you some idea. Make minor adjustments and see how the images improve step-by-step. Then edit ruthlessly. I end up with 5-8 images that I actually keep.
I personally like flashes for their show-stopping action, but others will disagree. It is not easy to make a flashed image NOT look flashed. I work with diffusors, head angle, head position, alter ratio between flash heads, exposure compensation, plus reflectors. Takes a while to get comfortable with it.
Below a Masdevallia zahlbruckneri.
8610-20.jpg