Just for reference, Camei is one of the most extraordinary and greatest Dragoons we have in our server. That guide will be invaluable if you read it. That being said, Camei also likes to PvP.
I am a strictly PvE Dragoon so I'll give you the base of my build.. Keep in mind that as a Dragoon that later you will probably be spamming 1-2 skills over and over again. Here are your main attack skills, listed in order as you get them:
-Storm Blade
-Spear Jab
-Spin it Bear!
-Time Reverse********* THIS IS THE MOST IMPORTANT SKILL EVER
-Cross Cut
-Mega Storm Blade
-Chain Shield
-Rolling Ground
Here is a build that pretty much resembles mine.
http://irowiki.org/~...500033035151151
You can mess around with Awakening skills and the Ultimate because you can use Dragon Dive in PvE if you so desire, and ultimates are always fun. I wouldn't add points to the Defense/HP line down the center of the Knight branch until way later, after you've gotten all your Attack skills out of the way.
Combos typically consist of:
Cross Cut + Spear Jab
Spin it Bear + Rolling Ground -- for mobs and this creates great DPS for bosses as well
Spin it Bear + [Mega] Storm Blade / Chain Shield -- either works
Spin it Bear + Cross Cut
Cross Cut is great because it hits knocked down enemies and enemies that are still being launched. Time Reverse lowers the cooldown/casttime on your skills while you have it active, but it drains MP per second. Rolling Ground is great damage and you're invincible while using it. For armor later, you'll want the Chaotic sets at 3/3 for Critical Damage.
Just a quick note on some ideas you may have: passives that add ATK like Sword Mastery are generally useless. Also, Strength is a useless stat and if you stack it you won't gain much ATK. Stacking stats comes much later in the game but you should know these things.
This is a very general overview and I recommend you read Camei's guide thoroughly.