2 things:
1) Using the Environment
2) Fluidity and weight behind the strikes
The Avatar franchise is great at this, because two of the four forms of bending involve the use scenery quite heavily.
Here is one fight between two earth and metal benders from Season 4 of The Legend of Korra
Look at how much of their environment they use, not only that, but the show is animated beautifully, fluidly, and with a lot of weight behind each action.
Damn, earthbending is cool.
An example of a terrible is this one from Halo 5.
Its slow, the punches have no weight, there is no use of the environment (or the other 6 characters in the scene, for that matter) and in the end, what should have been a rapid, high-stakes fight between two super soldiers, at the top of their game, with years of extensive training and combat experience, turns into what looks like a bar fight between two pensioners fighting over a bottle of beer.
At 15:00 mins in, here is a great breakdown of this entire sequence, and why it is so dumb.
EDIT: Also, anything this film does is 10/10