New Player: PvE P/P Crit/Precision Build?
https://forum-en.gw2archive.eu/forum/professions/thief/Build-End-Game-Fractals-P-P-Build
When your leveing your gear should look like this
Power (Level 1-20)
Power/Precision (Level 21-54)
Power/Precision/Critdamage (Level 55-80)
For traits I would pick up Preparedness first (15 in Trickery), then rush for Executioner (30 in Critical Strikes), and finally fluid strikes (25 in Acrobatics).
Toughness and Vitality are completely useless for a Theif, even end-game. Your survivability is skill based, not gear based.
For food I’d just use whatever you have lying around, leveling is extremely easy. If you do want maximum leveling speed, make sure you pick up the “Gain swiftness on kill” trait. For food I would go something from the On Kill table (http://wiki.guildwars2.com/wiki/Food#On_Kill). The “Spicy Meat Kabob → Plate of Truffle Steak Dinner” will most likely be your best damage increase.
Nuances? Never get hit, EVER. Also don’t get too reliant on Rolls cause you won’t be using them in dungeons.