So basically, the first way I can think of getting weapon experience is killing badies. Another one i can think of is learning from fellow players. What if, there were different kinds of classes of weapon experience. Like, one enemy requires a sort of \"piercing\" attack with the weapon you have, so if you have a sword, you stab the monster with it. Or a more common one would be slashing dmg and so forth.How much experience you get depends on how \"hard\" the monster is. Once you gain enough experience in the category it requires, a master can teach it to you.
A way to implement the special feats into the game is how SWG did it. You get these macros(or whatever you call them) and can put them at the top of the screen and assign a hotkey to it. So when your fighting, you can select for example...disarm, and it appears in a window until it is used. If you have more than one you want to use, they stack and happen one after the other.