Choose a location where you want the tree to fall. Ideally, this should be clearing where there are no power lines, houses, vehicles or people nearby. Avoid cutting the tree down into another tree, because flying branches can result in serious injury or even death.
Prepare an escape path by clearing space around the tree so both you and the spotters can easily get to that path and clear the area as the tree falls in the event of an accident or unpredictable tree behavior. Everyone should know where the escape path is and be in agreement that the path provides the safest and fastest way out of the cutting zone.
Remove any low brush or branches around the tree, since they can affect how the tree falls -- and you don't want any obstructions in that path.
Undercut the tree by making an incision with a chainsaw into the trunk at a 45-degree upward angle in the side the tree is supposed to fall toward. The cut should go at least a quarter of the way into the trunk for best results. Make a second straight cut on the opposite side about an inch higher than the initial one. This helps dictate the direction the tree will fall in. The two cuts should not intersect each other. The closer to the ground the cuts are, the better.
Hammer a wedge into your second cut if the tree hasn't tipped already. The wedge will force the tree over the angled cut and the tree should fall where you want it to. Spotters around the tree can verify appropriate falling and warn of any perceived dangers.