Let the mama do her thing. Give her plenty of her own privacy, don't bother her too much. When you do check on her and the kittens, just be sure she hasn't pushed any out of the "nest", and that they all are warm. That's about it. If any are sick, you will notice it. If any are potentially terminally sick, the mom will push them out of the nest.
Make sure she's nursing, and spending most of her time with the kittens. Outside of that, she should have everything perfectly under control.
Also - get her onto a high protein diet. I recommend "Indigo Moon" by solid gold. The less Ash in a food the better. Remember - the food the mother eats directly reflects the quality of food the kittens are getting. Indigo Moon is only $12 per bag, it should last 2-3 weeks. Keep her food and water dishes full and clean, with a litterbox nearby her "nest".
If you have any more questions, feel free to ask me.
