I like this. One suggestion I'd offer is to use a shoot through umbrella with your flash mounted on a stand. The shadows from the flash are pretty harsh in this pic and the umbrella makes them nice and soft. It makes it a bit more of a production to shoot (though still fairly portable), but the results are pretty dramatic. They are inexpensive and offer a huge bang for the buck. They work well for portraits too.
2 really horrible images that may serve as examples (I was going to shoot some flowers outside but it started to rain, so moved into the nearby shed):
Off camera flash without an umbrella (notice all the harsh shadows)
Off camera flash shot through an umbrella (notice how all the shadows are much softer)
Also possible you liked the harsh shadows, in which case never mind