Traiting
20+ Arcana, 20+ Water, rest as you see fit. That is the baseline for the majority of good specs.
Sample S/D: http://gw2skills.net/editor/?fEAQJArYhImkblx5gjDAEFmciQRFOUeMTO2A
Sample D/D: http://gw2skills.net/editor/?fEAQJAoYhEmkbwx5gjDAkHmcCLiCPUeMTO2A;TgAquMeJ8yWjrLZNjCmiA (copy-paste)
Fire is a bad trait line. Earth is situational at best.
http://www.youtube.com/user/IntigoGW2
It depends mostly on what you wish to achieve. However, you can’t really go wrong with 20 points in water since it’ll not only give you some vitality and healing power (which you’ll make good use of), but it’ll also give you a good heal/condition removal each time you swap to water (and it’s aoe too). With minimal investment in Air or Earth, you could get Quick Glyphs and/or Earth’s Embrace, which are fairly decent too.
As for the randomness, it’s not as random as it may seem. The major themes are Cantrips (Water), Signets (Earth) and Auras (Air/Water). I suggest that you look up those builds, they may give you some insight in how to pick traits.
its a good idea to get the basic stuff down first and branch off from there.
the linked d/d build above is pretty standard.
it works in all areas of the game and is very good for understanding the basics of swapping elements, combos for the ele, aura, healing, and how to tank.
for me it was a long road to get to the point of using d/d and then another road to get semi decent with it. Once i got a ways down it though its pretty impressive and feels something like driving a fragile race care might be.
very exciting and pay a lot for mistakes.