I have a few action scenes in Jim's Days however, the thing about it is that, you gotta find a good balance of time and story for it :U It's not a mindless start fight>Fight>end fight, it has to go from a to b. Why are they fighting? What will they gain? How will they get out? Who's stronger?
After determining the story aspect, let's talk movement and paneling. Lines, lines everywhere. Indicate action lines to speed movements up to get a better sense of how fast and strong they are. Adding dynamic to the static perse. Speaking of, study dynamic poses and how exaggerated they are in a fight scene, things might look better a bit bigger or a bit smaller, just see what works. Watch fighting scenes in movies, especially martial arts based ones if it's hand to hand and pause at opportune times where the action is clear and powerful. Draw that. As For paneling, regular boxes are boring? try to experiment with the shapes, making it more angular, short but long.
Lastly, timing. To transition into this, keep note that the smaller the panel, the quicker the time frame within it. If you want a fast paced comic, make sure that there are more smaller panels than big ones with the latter being used for the really dramatized action like a colliding punch or the epic finish. However, don't pull a Dragon Ball where a fight lasts 40 episodes. Make it short an sweet, enough to entice the reader without boring them. A couple of pages should do, but always remember the reader getting bored :U