most of mine are crappy, both with my mobile phone and with my camera. i delete more than i keep, and sometimes its a matter of having the camera aimed at whichever rat i want pics of, and hope that he/she will sit still long enough for a somewhat decent shot.
good settings on your camera include an "action" mode, to catch the fast little buggers, but then reset the focus to "micro" (often a flower) so that they don't get blurry so up close. if you had to pick one or the other, i'd say just take lots of "micro" photos and hope they stay still. i also have a "soft flash" which doesn't white them out, but try to take pictures in a well-lit room anyway (sunlight is way better than lamp light).
First it's good to let them have playtime first, that way they are less active. Take lots of photos, using proper settings on your camera. I put mine in a tree outside, so they don't have too much space to roam. I put a playpin at the base of the tree in case someone falls. The grass is soft so I don't have to worry about that, just escapees lol
And it's good to have a decent quality camera and light. Cameras thrive on light!