If your problem is along the lines of treating debates as competitions and getting caught up in winning the argument rather than finding the truth, I can completely relate. What I've found extremely helpful is trying to be mindful of that hazard when debating. If you notice yourself, say, tearing down your opponent's argument over what you know to be an easily fixed flaw, give yourself a bit of negative feedback (no! bad!). On the other hand if you notice yourself acknowledging a flaw in your argument, publicly renouncing a previously held position or otherwise changing your mind, give yourself a mental pat on the head (nice! good job!).
It took me a long time but if I notice myself weaseling around and subtly changing my argument to avoid being wrong I get an instant, intense sinking feeling in my stomach. Likewise, if I say something like, "Wow, yeah good point, I was definitely wrong there," I get a blossoming glow that spreads up my chest. These physical reminders are extremely reinforcing and I've completely flipped from hating to admit fault to really appreciating the experience.
Of course, its still reeeeally easy to push these cues out of your head if you're emotionally invested in a debate even a small amount. Constant vigilance!
Really new to this site, I'm hitting a problem I've experienced in other aspects of my life as a student, employee and comedic performer: I'm extremely rude. I don't realize it at the time, thinking that I'm just being blunt, forceful and direct. In the sense that those can all be definitions of similar concepts, then yeah! Well, confidence in myself is a great asset, and I've turned it to positive effect, especially when I need to intimidate someone with a roguish smile and a calm, iron-hard assertion backed up by a blistering intensity (I sound like a Marty-Stu right now. Draco will want his leather pants back.)
But making rationally sound argument should not be about winning. It should be about accuracy, clarity and sanity. If you disagree with me on something I need to remind myself not to automatically fight. What good is being alpha when I'm ignoring my confusion and avoiding my embarrassment at possibly being mistaken. Not to mention that this is an internet forum, so limitations of the medium means attempting to look like a tough guy winds up hollow and sad, like a chocolate Easter bunny that's gone off.
Okay, I'm not one for similes, but I am one for trying to make myself more sane.