Ah the fight scene.
There are several elements that go into a good fight scene. You need
1) the build up. You need to create the sense of tension and anticipation that comes just before two serious fighters intend to actually unsheith their swords. You generally do this through something of a tense standoff with dialogue, especially if you've got two REALLY good fighters or very powerful characters. They will test each other before actually engaging in combat verbally. This gives you a chance as an author to make it clear what their relationship is ( are they total strangers to each other? old friends? have they fought before? are they enemies? etc ) The readers need to understand this even if they sort of already know, make it stupid clear. This sets the scene for next stage. I can see you've already taken care of this stage more or less.
2) The Evaluation - Normally powerful fighters will, again continue to test with lesser moves before they unleash the powerful stuff. They will see how their opponant reacts to a lesser strike in order to get an idea of how to more effectively use the 'big guns' so there should be a few pages ( probably 2-3) of them crossing swords. Some parrying, dodging, disappearing, whatever you want for them to come to a quick draw. No dialogue generally here. Depending on skill variance between fighter or equality, some minor dramatic injury ( such as a scrape on the cheek ) may be sustained.
3) The Posturing - Now they both have an idea what they are up against. They will generally now posture and try to fake the opponant out as to what their next move will be as they consider it. This is another opportunity as a story teller to give further dimension to the characters as fighters with a bit of dialogue. Usually at this point they will comment on their opponant in some way. " Ah, you've gotten better since we last fought." or " You never did block your right side well. " You get the idea. Generally they will move towards taking the ideal position for their first true strike.
4) The Real First Blow - Now the opponants know what they are up against and thus will have chosen probably a lower 'first' move that is significantly powerful. They will now unleash this move on the opponant. This will generally always result in either one of three ways, the two fighters unleash equally powerful moves at the same time that cancel each other out, or both dodge/evade/parry their attack then ridcule them, or thirdly while they manage to avoid it the brunt of the assault, they still take some minor dramatic damage.
5) Recovery and Second Blow - Now both opponants need to recover so they will move to more defensive positions and ready the next attack. The Second attack is usually more powerful/crafty/creative than the last one, and is generally ment to manuver the opponant into the most susceptable spot for the final attack. This attack is usually too powerful to just cancel each other out, and thus is almost always dodged or parried, with or without injury.
Repeat step 5 for a third, fourth, fifth, and so on blow as long as you like, adding witting quotes, commentary and insults between the two combatants is generally recommended where appropriate to do so. In general you want to escalate it in terms of property damage until you get to the --
6) Resolution - This is where the fight ends. Depending on the kind of fight you want this can result in a bloody draw or a clear victory. Sometimes it is neither.
A few points to remember however when planning the fight; in order to keep it interesting the tide of battle has to clearly sway one way or the other and then the other person has to turn it some how, so that the battle isn't clearly being won. There has to be injury, loss, blood, property damage, etc. If there isn't any kind of see sawing it gets really boring. Two very powerful and experienced warriors aren't going to fight feebly and they are going to go all out. They will injure the other person. So even if there isn't a clear victory, you should plan for injury to the characters beyond little scratches. Its the excitement of seeing how they manage to avoid being defeated while still suffering injury that makes it exciting and the injury makes it more suspenseful.
You should script the battle and if possible get some friends to help you act it out so that you can see how well it works and get feedback. If you know someone who is a martial arts or fighter type person ( any type of fighting), getting their advice and feedback helps as well.
When you actually get to the point of drawing it, you will definately want reference. I'd suggest actually looking to movies for dramatic fight choreography. Get yourself a dvd of Gladiator, Troy, Highlander, Lord of the Rings or any other movie that has good fight scenes with swords. pause it and study how the shots are blocked at the hight of battle. How the forms are, where the swords go, how they are dodged or not, Then take those and exadurate it a little. Make it a little faster, wider, harder, heavier, etc. Make sure you pick interesting angles that make sense. You want to put the viewer in the action. You'll want to pick other 'camera angles' than just the typical side on or front on view. You definately want to show the whole body in big clashes. Try not to do too many headshots, you want to show more body and area shots. Although closeups of the injuries or critical strikes are appropriate. For really powerful strikes, don't be afraid to do some explosions or energy eruptions, especially considering you've got what appears to be a fantasy comic going on.
If you want to see my fight scene between two of my most powerful characters and how I handled it, you can read this one ( which involves a sword fight.. of sorts )
http://shifters.keenspace.com/d/20031219.html
Read from there to the end of "Dogfight". You might find some insipiration. I'm better at showing than explaining.
Hope that helps.