You can’t. Not a generically good fight scene. Just like a good love scene, “good” for a fight scene depends on the literary purpose and the audience.
Let’s assume, though, that you are writing some kind of action adventure yarn — I’m qualified to advise on this because this is what I write professionally, and my fight scenes trigger your mirror neurons (apparently) – here’s what I’d tell you over a beer.
Have a Model of How the Relevant Martial Art Works
By “model” I mean that you can describe to yourself how this kind of fighting works. E.g. is it all “cut parry cut”, or about crossing blades then working on the blade, or wrestling or what?
It helps if your model is based on reality or at least experimental reconstructions — if you’re using any European weapons, check out Youtube using the search term “HEMA”. You can of course make everything up, however more and more people are becoming HEMA-literate, so there is a good chance your book will date horribly.
The model should account for all the equipment used by your combatants, e.g. What is a shield for? What weapons break the armour? This ties the combat scene into the rest of the world story and brings to life the military culture and technology. For example, if combat requires a shield, then losing a shield can drive part of the plot. Oh, and, whatever you do, don’t treat armour as set dressing or costume. If it doesn’t stop weapons, nobody would wear it.