There isn't really anything to it besides proper diet (grains, grasses, some seeds, no animal protein is required), constant supply of water, and both sexes present. Leave them alone as much as you can, and keep them in a low traffic area of the home away from household pets. Leave the colony intact, as moving them around really stresses them out, and mice can be a pain to get started breeding anyways. They are very easily upset, and it doesn't take much for them to decide to eat their litter. So remember a constant supply of food and water and leave them alone
Another tip is to avoid using water dishes and stuck to bottles. They will fill up the dish with shavings, feces, and urine almost instantly it seems. Good luck :thumbsup: