Determine the clear fall path. Along with a clear landing, this is the most important factor in deciding what direction to fell a tree. Visualize the fall path in all directions and identify those directions that are free of other trees. Finding a clear path will eliminate lodged trees, throw back, and damage to the tree being felled as well as the other trees.
"I start the top cut of the face using the gun sights on the saw to make sure it goes exactly where I need it to go. There is a black line painted on the side of my saw. Where that line points is where the tree will fall."
Always observe the lean of a tree. It is generally easier and safer to fell a tree in the direction that it is already leaning. This makes for a cleaner fall and eliminates the need to use wedges, allowing gravity to do the work.
To make removal easier, fell the tree so the butt faces the skid road. Also, fell the tree consistent with the felling pattern of other trees. This also makes for efficient limbing and removal. Fell in a direction that will minimize the chance that the tree will roll or slide.