I write slipstream by going slipstream. I coreograph my fights by experiencing them in my imagination. Most of the time, I'm simply describing what I see inside my head. Everything else disappears. So, I usually become the protag or the hero or victor in the melee. Consequently, if I find that I've gotten sloppy on the way to the fight, I'm usually sloppy within it. Which means the fight goes bad until I can turn it.

Advice I usually give in critiques/edits: be brief. Use strong, direct verbs. One action per sentence. Use complex/compound/complex-compound sentences to slow the action or add drama, but never to encompass an entire fight sequence. Nothing is ever 'close' it is either a hit or a miss. Show me the blade swishing past my eyes, don't tell me it missed by a hair's breadth. If the fight goes on and the adrenal surge begins to wear off, show it by picking up details like congealing blood, dragging leg, diminished field of vision due to blood or steel in eye(s), etc.

I agree with R.L. here.

I would also point out that how the experience effects the character, and how said character reacts, is as much characterization as it is action/plot/etc. And people react differently in fights. Some people laugh from nerves, some cry, some purge their bladders, others purge their bowels . . . For myself, I'm manic until the first strike; then I'm weirdly serene until the conflict is over. This is not because I've been in many fights - I make it a habit to avoid them - but because I was in a household in which the belt came out and, as they say, all hell broke out. It was a recurring theme of my childhood from 1970-1977. You get used to being hit, and you can look a guy straight in the eye with your nose broke and tell him to very calmly to back off or suffer the consequences. The adrenal rush comes before and after for those of us blessed with PSTD. When the fight is on, time really does shift to half-speed. Thought ceases. If there is mortal peril, the body takes care of itself. The consciousness insulates itself and the beaten child becomes dissociated from the external world. During that fleeting dissociation, such a person can commit what seem to others as grave atrocities simply because his animal self feels threatens and is driven by the instinct to survive - at whatever cost. So . . . at the end of the fight - that's when you either freak out and stomp and cuss the adrenillin off or you shrug and make some glib comment about "warned ya," or "that was intense".

Another funny thing . . . I have almost no recollection of the serious fights I have been in. I was either too drunk or too freaked to really imprint it on my memory. Stories I've heard from others are certainly interesting, but I don't really recall much detail. And, to be frank, most of those fights were stupid cases of me having to put my ass where my mouth had gotten me. The two worst were cases of butting into someone's else business; trying to play saviour or something. Thank God I lived through that foolishness . . .