I am always impressed when a person can instantly looks at a tree from dozens of feet away and say, "Well you got there a Honey Locust" or, "I see you have Shagbark Hickory and White Oak on your property."
What are the most important factors you look at when being able to identify a tree so quickly? I assume leaves are the major takeaway but there are people out there who can identify trees in the middle of winter with no leaves.
Yes, you can. Experience helps a lot. For instance, I did forest mapping one summer, so I spent a lot of hours walking through different stands, glancing at trunks, and saying, "This is dominant sugar maple with a lot of basswood and poplar...."
Just by bark (which allows year-round ID), it is usually as easy to tell a white oak from a red oak as it is to tell your friends Bob and Bill apart (both blond hair and 5'11").
The advantage of bark is that often the twigs and leaves are too high in the air to be of use.
The favorite game in my family is Dead Tree ID as we look at fallen trees on a walk, ones that have no more leaves. We're pretty good, because even when the bark is gone, a tree species has a form, if you just use your intuition and don't try to think too hard.
In forest ecology lab in college they emphasized twigs. Each twig and its bud are distinctive by species. But to make full use of twigs in a mature forest you have to be a really good climber.
You can narrow things down with the branching pattern.
Opposite branching: Maple, ash, or dogwood. That's it, for eastern U.S. possible firewood in the woods. Dogwoods are short, and have their own form, so opposite branching in taller trees is a maple or ash, and the barks are very different.
Alternate branching: In this group would be the others -- oak, hickory, locust, tulip, cherry.
Leaves on the tree or ground can be used to verify. But leaves are reliable to get you in a group -- like the white oak group, the red oak group, or the maple group. Just by leaves it's a little bit of an overreach to say, "That's a Norway maple; that's a sugar maple; though they do tend to be a little different in the amount of indentation.
If you move a long ways, it all changes, like if you move from Vermont to Georgia. But the basics are similar.