I just got back from my Tae Kwon Do class and it was the most fun I've had in some time. I can sum it up in two words. WEAPONS CLASS!
In my Tae Kwon Do class, we use two main weapons up to Black Belt. First is the escrima stick. It's basically just that, a stick. Easy to hold and strike with. The other is the bo or staff (depending on what you want to call it. The bo is typically about as tall as the user. I'm about 6' and I have a 5'6" bo and a 6' bo. I like the slightly shorter one.
Many of the teen/adult students are also part of the school's demo team. They had a demo scheduled, so the class was a little smaller than usual. But that was a good thing because we got in MORE practice with weapons, including an opportunity to spar with weapons.
Like practicing in any other aspect of martial arts, sparring with weapons is very different than practicing the fundamental techniques. The three people I sparred with escrima and bo focussed too much on "textbook" techniques and didn't consider a comprehensive strategy. Their strikes became pretty predictable as a result. For example, rather than trying to strike with my weapon, I simply used it to push my opponent's weapon hand aside and then hit with a regular punch or kick. I did a little of the same with the bo, trying to shove the other bo aside to create an opening so I could strike.
What does all of this have to do with writing though? More than you might think. For one thing, if you have your character go through weapon training, particular close-in combat, don't make the transition too easy. Have them acknowledge the difference between form and fighting. For other weapons, make sure they notice the difference between training in a controlled environment and actual combat.
I'd also say that modern science fiction readers are much pickier about details with technology and combat. Readers aren't as willing to simply accept techonologies that blatantly ignore the laws of physics. Same with weapons and combat. Writers need to include some credibility in their tech and fighting. Researching some technical theories is much easier today thanks to the Internet, but fighting tactics aren't quite as easy. I suggest that if you don't have training that you should let somebody more knowledgable read your fight scenes for credibility. I've critiqued some scenes in critique groups that bent body parts on completly unbelievable angles before moving to the next move.
Another idea is to just try to act out the combat scene. Anything to visualize what you do and then write it down.
Time for me to hit the showers and...