I have been having trouble with the macro shots of miniature all the time, especially when I haven't finished and I don't want to pull out my Cannon just yet. So what I did is that I used a which foldable drawer organiser from Ikea (I'd write the proper name later) and push the Ikea deak lamp right at the angle where half the light shine through the top of the box, and half the light shine straight at the miniature.
Another way to look at this like you have a open box made with whitw cloth, put it side way opening facing you, then put the lamp at the top edge of the open so that the side on the top helped defused the light and thw front opening let direct light hit the mini.
The result is a lot better then just shining the ligt straight at the miniature, and I haven't spent any money on it....
... but my painting is pretty average this time, I know...