Contrary to most sword fights we saw in the movie,practically most sword fights end within 3 seconds or less and within 1-3 technique (There are cases it exceeds 3 seconds or more than 3 technique but let's tell that story some other day).For sword clashing (I assume you mean direct block like the one you usually see in the movies) against another sword isn't recommendable as you might end up having two piece of the blade instead of one.So parrying technique comes in where you deflect the sword.
In short it's quick and fast.
Fights are fast. They can end in one hit, or two. You never know, but you just keep trying when in that fight.
Hmmm, books. Read up on Musashi Miyamoto and his epic duels. They normally only last 2 or 3 movements and each movement involved a lot of aggression.
There are also some very detailed fight descriptions in old New Zealand land wars between soldiers and natives with swords and other dueling weapons. Back then, soldiers fought using feints and thrusts.
It depends on wether you want to keep an historical context or a fake "hollywood" context.
Swordsmanship, no matter the style, is a quick and violent profession.
It can cut through ligament, flesh, and bone. The pain from a non fatal stab or slash can be excruciatingly painful. It can cause shortness of breath, nausea, sweats, and unconsciousness from blood loss.
As for unarmed combat, learn some fighting terminology. Just write what's in your head.
Read up information on the Samurai and Ninja.
http://www.akban.org
Read samurai related manga like blade of immortal (not the first book which had little action sequences) so you get roughly ideas of how fights are composed of?
Samurai fight with honor... face to face. Ninja kill while their victims are unaware.
I want have an idea of how a fight can be, like swords clashing, feeling blood drop, how the pain can feel or the movement of a fight.
I really have no idea and I have read lots of books but I need some help really, so please don't be harsh on me. English is my third language and I'm only a kid, so I'm not that experienced (even after reading a lot)
