Sword-fighting tips, from a fencer
I've been fencing for only a few months, but in the time, I've noticed a few things that could help with writing in general.
You don't talk during a bout. This is both a rule and common sense - you get breathless, dancing back and forth, there's no time for a homoerotic back-and-forth. Save that for before, or after.
It's fast. Incredibly fast. Granted, this does depend on which sword you fight, but that's only because of the different rules - good fencers are fast and smooth and it happens so fast it's hard to see the blade move.
Speaking of which - good fencers are smooth! This goes into several areas.
Footwork - incredibly important. You can recover from sloppy swordwork, but footwork is foundational to victory. Fencing footwork looks a lil goofy, but it does genuinely help with balance and speed of movement.
Most of the weight is on the back leg, for launching off with, or, if retreating, the weight shifts to the front leg to launch you backwards.
Swordwork - sloppy swordwork is... alright, but not ideal. For most fights, you want to work on point control - where the tip of your blade is going. I struggle with this myself still, but common practice includes knotting some thick rope, dangling it from a branch or something similar, and letting the rope sway, then trying to hit the knot.
Additionally, any experienced fighter will be incredibly aware of distance - what's the closest they can be without getting hit? How far away can they be but still able to hit? These things determine duels.
How you hold the handle of the sword can actually help your chance of winning quite a lot - one of our instructors says he holds it like you'd hold a bird's body - firm enough so it won't fly away, but gentle enough to not hurt it. This means, that when you go to strike, you can squeeze your hand, and the blade will clear the distance much faster.
Good parries can determine your victory or loss. Often, a parry-riposte can get you the point, or win you the fight - where you get the opponent's blade away from you, then hit them quickly as they're vulnerable.
Depending on your intent in a fight, you may want to dodge instead of parry, though - launch yourself backwards when you expect them to strike to make them miss. In fencing, this would mean (in sabre and foil) that the priority (and ability to get a point) switches to you, whereas in a real match, this could just give you distance if you need to plan a new attack or get away.
Watch fencing matches! If your character is:
Slow and methodical, psyching their opponent out - watch epee
Fast and brutal, hitting hard and relentlessly - watch sabre
Flourished and dignified - watch foil