I started sparring last year, but I sucked. So. Bad. I used to be -300 in spar. But as I continued sparring, I began to see improvements, and eventually my spars became positive. How? I'll tell you.
First of all, where should you spar?
If you want to challenge yourself or increase your spar wins, then spar at the Battle Arena. However, if you were just on a losing streak at the Battle Arena or need more practice, spar at Master Li's (I recommend sparring here to warm up after a long period of not sparring so you don't risk losing a spar.)
Now that you've chosen a place to spar, how are you going to win?
The Do's of Spar
Make sure you have good Wifi. Otherwise, you could lose a lot of spars (or get rage from lots of players.)
Come up with a technique. For instance, I use a technique called the C-technique. It's a simple technique where the person moves curved and then they slash their sword at the points of the C. (Not a very good explanation, so I'll show you a picture)
Attachment 15970
Such a beautiful picture, isn't it?
Anyways, the red circle is you. The curved lines are how you move and the blue dots are where you slash your sword.
Vary your techniques. For instance, if you use the C-technique while the opponent is far away, you could use a different technique when the opponent moves closer to you instead of using the C-technique in the opposite direction that they're moving towards. Maybe go behind them when they're about to hit you or something.
Have good sportsmanship. It makes your opponent feel more confident if you're about to spar them. So don't forget to say good luck (gl) before a spar or good game (gg) at the end!
If you have a laggy opponent, predict where they'll move next. Slash your sword at certain spots or slash it in front of them to register a hit.
Before you spar,
get to know your possible opponents. Watch spars or look at players' stats to get an idea of what kind of sparrers they are.
Concentrate. If you're thinking about what you're gonna eat later, then you could lose focus and get defeated.
Be patient. If you're gonna slash your sword downwards near the top wall, expecting them to run up and be hit, they might go and hit you in the side. Wait (by this I don't mean stand there and watch the opponent move around) until you've got them in a place where you can easily register a hit.
Take breaks. If you're losing a lot, then that probably means you should take a break for a while (maybe a few hours.) Later, you'll begin to win again.
And, most importantly,
practice. Like everyone says, practice makes perfect. Practicing gives you more experience and helps you develop new techniques.
The Don'ts of Spar
Don't stay near the wall. Your opponents can easily flaw you if stay near the wall for the entire match.
Don't sword spam. Your opponents can easily hit your vulnerable spot (aka the area where you aren't slashing your sword.)
Don't run around non-stop. What I mean by this is don't make your opponents chase you around for a long time while not slashing your sword. Otherwise, your opponents will have an easier time predicting where you'll move next.
Don't run straight. If you run straight, the opponent can easily perform a hit combo by simply hitting your vulnerable side. The more you run slant (zig zag), the harder it is for the opponent to hit you. Don't run slant too much though, as you could suddenly run into your opponent.
When someone is just standing there,
don't charge at them for an attack. If you do, they'll make their move and get a free hit. Don't just stand there and expect them to move either. Instead, run up to them (but not too close) and immediately run away. They'll move, and the actual spar match will begin.
Don't talk during spar. It gives your opponent a free hit.
Don't underestimate your opponent. Sparring people with negative spars doesn't mean you should take it lightly on them. They could be going positive as well.
Don't rage at people when you lose. It makes you looks like a bad sparrer if you take your anger out on your opponent. Instead, think about the mistakes you made during the spar and how you can improve your performance if you spar the opponent again.
Don't think about winning. For me, it naturally makes me take it easier on people, making me lose spars.
In the end, I may not be as good as Thallen, Rufus, etc. But it's not about appearance (sword, clothing, etc.). It's about performance.
P.S. For PC users, check out Thallen's thread for more tips:
http://www.graalians.com/forums/showthread.php?t=16061
Good Luck! ;)