The Tale of Painters Blog has a nice tutorial on photographing wargames miniatures.
To their tutorial, however, I would add the following:
1) Shoot in RAW. RAW is the unprocessed data collected by the sensor. If you shoot in JPG format, the camera itself takes that data and converts it to the best of its ability.
2) Skip the in-camera white balance adjustment and instead invest in a copy of Adobe Photoshop Lightroom 5. It’s $149 on Amazon (and often cheaper at the link), and if you already own a DSLR, is a no-brainer for sorting and organizing photos and making them look their absolute best.
Lightroom allows you to import the RAW photos on your camera, and then adjust the images until they look right. Instead of going through all the custom white balance effort in your camera, you can adjust with one click. If you’re using a white background, you just select the white balance sampling tool, click on something that’s supposed to be white and the software handles it automatically. You can also sharpen the photo, adjust the color tones, the brightness and lots of other things. I tweak every photo I take, and the combination of RAW and Lightroom makes that possible. This applies not only to shots I take of miniatures games, but also to family photos and to the golf course photos I take for my other blog, GolfBlogger.Com
When you’re snapping photos on the move, as at a convention, or a family gathering, or on the course, you don’t want to halt the proceedings so you can whip out your grey card and adjust the camera. Shoot away, making sure that at some point, you include a shot of something greyish-white. For me, at wargames conventions, it is often the white belt on a miniature, or a piece of paper. Other times, I’ll just lay the grey card down on a table and take a photo of that. Those will be enough to give you the proper reading on the camera. Then, later, you can use Lightroom to automatically adjust every photo you took in that light to match that “reading.”