Let me start off by saying that I know lighting a cigar is not hard, but I receive many requests from people on how to do it correctly, so I figured this is the best place to share the knowledge.
To light your cigar you need the correct lighter. Some cigar buffs use cedar strips for the job, but I find these hard to carry around. Most people prefer to use matches or a butane. When using matches, wooden ones are the best because they look cool and they stay lit longer. If you opt for a lighter, make sure it uses butane fuel. Why? Well, just about anything else that you could use to light the cigar will effect the cigar's taste. Regular fluid lighters have an odor that can be transferred to the cigar if the flame is allowed to touch the foot.
Take the cigar in your hand and light your flame source. Slowly rotate the cigar in your fingers as you lightly toast the tobacco on the foot of the cigar. Try not to let the flame touch the foot as you rotate the cigar in your fingers. Put the cigar in your mouth and continue to light as you rotate the cigar, gently puffing in every few seconds.
When the cigar is lit, remove it from your mouth and look at the foot to make sure it is burning evenly. If it isn't, you can gently blow on the foot causing it to ignite the tobacco which is not burning or you can apply a flame to that area. If you have an area which is burning faster than the other areas, simply wet your finger and apply under the quick burning area, this should slow it down.