haha, well, it would be much easier to show IN game, but I can try to describe little bit here as far as No-Force sabre fights.
(this is ignoring double-sabre, by the way, because lunge is all you really need with that, lol)
Basically, blue only has two real uses. Lunge, and speedy attacks to throw your opponent off. Red and yellow are where its at, because you can get lucky with lunge-whoring, and it usually beats total newbs, but anyone beyond that, lunge whoring won't work. But absolutely switch back every once in a while to lunge--that'll throw them off. Just don't kneel down as soon as you switch, because they'll see what you're doing.
Which brings me to a good point. One thing you don't want to do, is develop obvious patterns of fighting, that your opponent will see through. If you roll around 3 times, then lunge--and repeat that pattern over and over again, anyone will eventually see what you're doing and counter.
Red is very good, mainly the straight forward attack, and the wide right swing. The straight forward attack (overhead, swing down attack) is excellent damage. Red's special (RDFA) is well... again, you might get lucky, but try to keep the number of times you use it against skilled duelers between 0 and 1, because it's the easiest thing in the world to counter.
Also a good tactic is to swing with red (either straight or right or whatever) and then either crouch or jump. If you notice them jumping over you to dodge your attack (or just plan their own) either look up, or jump to try to hit them with your attack. Using the straight down attack, and then following your opponent with the mouse, can be a very good tactic, because they can't get away.
Also, crouching after an attack (aside from being easier than crouching BEFORE an attack) can very often land a lucky strike, as it seems harder to defend against.
A good attack for both blue and yellow is the "hold attack, strafe left, strafe right, strafe left, strafe right" thing, where you kind of wave the sabre back and forth. That can be a good attack to counter Red stance sleepers (like me). You can be quick enough to get a yellow strike in and then roll away before they even finish the swing.
Yellow is a good stance. Again, being faster than red, you can really do a number on red sleepers like myself who have to wait for that one long swing before they roll away or jump back or whatever. I kind of think of yellow as the "dance like a butterfly, sting like a bee" stance, hehe.
And of course, yellow special (YDFA) can be immensely powerful when your opponent thinks you're using red, and they try to move in for the attack, only to get sprung from above. But careful, if they notice what you're doing, they'll probably either blue lunge you, which is painful as hell, or RDFA you, which can 1-hit kill you.
And again, even when using YDFA, or most other attacks, follow your opponent with your mouse! That way your sabre is pointed towards them, usually increasing your chance for a strike, and most importantly, protecting your back, the most vulnerable part of your body.
But, it's more or less up to each person to develop their own style. Practice is the only real way to learn, but these can be some helpful hints. And although I'm saying these things, another person may think I'm out of my mind for believing it. To each their own.
Also, something you may notice, is that N/F dueling can be almost a paper-rock-scissors thing, where you may beat Bill, and then watch Bill DESTROY Frank, but then Frank kicks your ass. And you're left scratching your head, thinking, "wtf, that should've been easier.." About 35% of a good dueler is the ability to adapt to whatever opponent he's fighting currently.
Hope at least SOME of that was mildly helpful. And again, almost anytime I'm on, I'm down for N/F dueling.
