This is how I duel a rogue on my Paladin:
Before the duel, I make sure I'm using a shield and retribution aura. They stealth at the beginning of the duel so they can cheap shot me, so I make estimations of we're their walking, and we're they're at, and I cast rank 1 Cosecration and pray they walk into it. I repeat this until either they've suceeded at cheap shotting me, or until I've suceeded if seeing them. After that, I stun them for 6 seconds with my Hammer of Justice, do all the burst DPS I can, drop Judgement of Light on them. I always try my best to out heal their DPS and still do damage to them at the same time. Usually when I go to heal myself and I believe their kick is up, I cast the first second of my heal, the cancel it. I watch them, and if I see an attempted kick, or if a few seconds pass, I cast a large heal on myself (of course, I will cleanse any cast-slowing poisons that may have been put on me). I try my best to win the duel without bubbling, but occasionally I have to, like when I find the rogue that stun locks me for the entire time of the duel, and takes me down to 10%. I also have my own little strategy that I've been thinking up for the past couple days. I almost always beat rogues in duels, but occasionally I'll lose.