While you can't avoid stress altogether, there are some things that you can do to limit its effects on the body. Get the proper amount of rest. A person that receives an adequate amount of sleep is more likely to be stronger and healthier than the person who tries to get by on a minimal amount of sleep. Proper nutrition and adequate protein intake. This is very important in the process of healing.
Antioxidants are especially good at keeping the body healthy and warding off cold sores.
Many people who suffer frequent outbreaks are found to be deficient in the B vitamins. Also, the amino acid, Lysine, is rapidly gaining popularity for warding off cold sores. For reasons unknown, some people seem to have a natural immunity to the herpes virus and will never contract it. Others harbor the herpes virus, yet show no outward symptoms. Though they themselves may never get a cold sore, they can still pass on the virus to an unsuspecting individual.