How can I make sure my orphan mouse lives without it's mother?

My cat found a little baby mouse so we decided to take care of it. It doesn't have its mother so I'm taking over that part. So far after all of the research I've done I have a bed ready with rice and a sock warmed up to keep the baby warm, and fleece for insulation, all in a shoe box. I've been feeding it every 2 hours and making sure its warm. I don't really know if there's anything else I can do..