A fire is an extremely important survival tool and can be used for the following purposes: purifying water, cooking food, creating smoke and light signals, providing warmth, keeping animals and predators away, drying your clothes, aid in the making of tools, and keeping insects away. Also remember that a few smaller fires provide more heat than one large fire. Knowing how to build a fire is considered to be the best survival skill to have so start practicing and become an expert.
Always have at least two, preferably three ways of making a fire on demand. With waterproof matches, a butane lighter, and a magnesium fire starter or firesteel you should be able to create a fire at anytime and any place no matter how harsh the condtions.
So the tip here is to learn the art of fire craft. Practice and become an expert. Your ability to create a fire is perhaps the most visible mark of an experienced survivor.