How can I learn to be competitive in PvP and WvW?

I am almost exclusively a PvE player and love exploring, crafting and opening things up in game. Every now and then I get tempted by the PvP and WvW areas but tend not to head there because, frankly, I don't know what I am doing. Besides the weapons tutorials on the Mists, what is the best way to learn how to play PvP and not seem like I am a complete noob? I am not looking for strategy per say. I am looking for some tasks I could do to understand how to become competitive and enjoy playing PvP or WvW matches.

This may be something other than what you are looking for, but the main thing is going to be to practice. PvE can help to some extent, but you really need to just get in there and start playing. That's the only real way.

I understand you're possibly nervous about not being able to contribute for your first couple times in PvP or WvW, but that's really just how it's going to be. You will get much better much faster by actually playing. People probably won't even notice, and even if they do, it's just part of the game.

Beyond that, the biggest piece of advice I can give is to be familiar with your skills. You will tend to get nervous in PvP, moreso than in pressure situations in PvE. Make sure you are familiar with your CC effects -- which skills they're on, how they work, how long between uses, that sort of thing. Again, gauging how effective each skill is will only be able to happen through actual experience.

Other than making sure you know how to use all of your skills (with focus on CC), you'll want to practice kiting -- again, this is best done against other players, but you can try kiting mobs around as practice.

Familiarity with other classes/skillsets will help -- I suppose you could try playing with all sorts of weapons/classes/races so you will know ahead of time exactly what to expect from every opponent. Jumping right in will still be a faster way to gain this knowledge than trying to prepare without actually PvPing.