Having adequate food and water
good personal hygiene
Getting sufficient rest
Keeping your immunizations up-to-date.
Develop a survival pattern that lets you beat the enemies of survival. This survival pattern must include food, water, shelter, fire, first aid, and signals placed in order of importance. For example, in a cold environment, you would need a fire to get warm; a shelter to protect you from the cold, wind, and rain or snow; traps or snares to get food; a means to signal friendly aircraft; and first aid to maintain health. If injured, first aid has top priority no matter what climate you are in.