Biggest tip - use digital zoom, take your photos from at least a meter (yard) away, and then crop the 'empty space' off the image.
This deepens the focal plane, so that all of the area around your mini is in focus. Also essential for taking a pic of multiple minis.
One other thing I swear by - I have a lamp that's a rectangular strip about 1"x15" of LEDs. Gives a great diffused light. It's equally essential for my painting - it can sit almost between my eyes and my hands, giving great lighting - and for pictures.
W.