Of course we have heard to ideally get 8 hours of quality sleep each night (which I agree is good so your body can use this time to repair)... but there are a couple of things I feel I should mention which may help to reduce the chances of a breakout or a negative effect on skin's overall health.
Make sure you clean your pillow case regularly. I change mine twice a week. I wash my bedding with a gentle fragrance-free detergent and do not use any fabric softener/dryer sheets. I also have long hair which I braid in order to keep it off my face during the night. Sweat, oil, dead skin cells... having these pressed against the skin cannot be beneficial.
Additionally, I would recommend keeping your hands off of your face--whether it is resting your face in your hands or to pick/squeeze at blemishes. I believe minimizing this contact will help reduce the probability of a breakout...or prevent it from getting worse. For those who cannot resist occasional extractions, remember to follow proper sterilization procedures...and resist getting carried away! It will cause more harm than good.