One easy and satisfying way to dive into winterizing the yard is, instead of raking and bagging fall leaves, to simply run them over with the mower to chop them up into a slow-release, nitrogen-rich mulch.
Resist the temptation to leave the leaves (no pun intended) as is. It may seem like a good idea to let them form a protective blanket against Old Man Winter, but it will actually smother the grass and could lead to pests and disease.