If you have more force powers available and are fighting single player (may also work in multi, haven't tried yet), use Force Run. It totally rocks in saber fights. The other person moves much slower than you suddenly, so you can just run around him and saber him in the back.
General fights with no force powers: Run, move forward and crawl at the same time for a forward roll. Rolling goes much faster than normal running, and you come in low, UNDER the usual defense. Only if they're smart enough to start swinging wildly or jump/walk away, they can get the first strike. Most multi players are used to run speed, and have adjusted their combat for that.
Jump on top of people. Don't know about multi, but in single player it knocks out the target for a moment, even with the Reborn Jedi guys. You can then saber em down when they get back up.
Use weapon 4 from a great distance. Just found it out last night, haven't played around with it much, but it seems to be unstopable with sabers, and therefor provides an easy kill.
Seeker Drone. It uses normal beam attack, so you can deflect it if you aren't busy. But then, you are keeping them busy with your saber attacks 🙂
Heal. If you have Force Heal 2 or 3, use that during saber fights if you don't have other important powers available (Force Run or so).
Set 'F' to Force Push, to break free of Force Grip (Can choose the power with 'Z' and 'X').
MOVE! A lot of people just stand there during saber fights, or just strafe left and right a bit. Run around fast, be unpredictable (and don't be unpredictable in the same way all the time 😉).