I could probably help teach you, though I should make a point that it's rather difficult to do this type of role-play at a 'free' level of role-playing rather than 'casual' or 'advanced' -- role-play duelling, especially when doing so [i]without[/i] using stats or dice, is all about the details and strategy, which usually can't be done in a couple of sentences.

If you're going to do it at a 'free' level, I'd recommend using stats and dice since they allow for more simplified combat that doesn't utilize elaborate tactics and mind games -- this allows for a much lower level of writing without any problems arising, since these 'Tabletop' systems are inherently designed for games that have minimalistic storytelling in mind (making them more ideal systems for people who don't actually know how to role-play duels well). If you want to learn proper role-play duelling, you'll want to do so at 'casual' or - preferably - 'advanced' level.

That being said, I could probably answer any questions you have about it if you send me a PM -- I don't have time to take on another opponent myself, but I'm always available to tutor.