I generally love writing large fight scenes where I can have my character jump from person to person. However, I need to write a one on one hand to hand fight scene and I am a little stuck on how to keep it going and intense at the same time. Any help is much appreciated.
Unfortunately, reading/writing fight scenes is not usually as exciting as watching one. What you want to do is keep the intense feel, rather than the play-by-play description. When you first start the scene, feel free to describe the punches, kicks, and counters that make the power balance of the charaters apparent to the reader. Then, taper off of the details and go with more generic but fast descriptions. Also, the faster the action, the shorter the scentences should be, in general. You can also add more details about how the fighters look and feel, like their ragged breathing or shaking sweat out of their eyes, rather than just what they are doing to hurt one another.
For example: At first, the two were well matched. Bob threw a right hook. The enemy countered with duck and a jab to the ribs. Bob watched for an opening, carefully analyzing his opponent's stance as they circled each other like tigers. Then, the enemy threw a flurry of blows. Bob was so focused on blocking them, he didn't even see the kick coming. He limped back to put some distance between him and his attacker, favoring his right knee...
Perhaps taking your fight scene out of your novel and writing it as a flash fiction piece might help with the action?
I took a Flash Fiction course for my Master's and restricting your scene down to like 500 words sometimes really helps map out a scene to get it down to just strictly feelings and emotions and really gaining clarity on a scene. You can even expand it to 700 or 1000. But I usually use 500 because it makes me hyper focus on the power of words and makes my selections that much more thoughtful.
However, since thisisNaNoWrimo and the point to all of this is to just get the verbal diarrhea out- maybe just write it with action as if you were an announcer telling everyone out in radio land what was happening- and then going back and "fixing" it during the editing process in December.