Trees should really be cut down by a professional tree removal company unless it is a relatively small tree. However, if you are determined to remove a tree on your own, there are a few steps you should take to keep safe. Dropping a tree has a few steps that should be followed in order to prevent damage to property and person.
Locate the direction that the tree should fall. If there is something valuable in one direction (such as a house), avoid sending it near that location.
Cut off small limbs with loppers and a tree trimmer. Cut out branches as high up as you can get. Use an extension ladder to reach the higher branches.
Cut off larger main branches with a chainsaw. For the higher branches, attach cord around the limb to be cut and then thread the cord over another branch and down to the ground. Tie the other end of the cord around the base of the tree, and then cut the branch off. The cord will keep it from crashing to the ground. Untie the cord at the base of the tree and gently lower it to the ground. Do this with each of the large branches so that they don't cause damage from falling.
Cut the tree down at the base. Cut a V shape low to the ground on the side of the tree where you want it to fall. Now cut a straight cut into the tree on the opposite side. Make sure this cut is higher than the other cut. Be prepared for the tree to fall as you do this because you are releasing the tension in the tree trunk created by the V shaped cut.