1. Get out presearing by getting a secondary profession and then letting Rurik and the henchies clear out the Grawl in the caves.
2. Get a group of friends or guild mates with level 20 characters, preferably with run buffs.
3. Group runs you from Ascalon City to Sanctum Cay. (Ascalon -> Yaks bend -> bergen hot springs -> temple of the ages -> fishermans haven -> sanctum cay)
4. Group does Sanctum Cay mission. Even if you die if the party wins you get credit, so either die early and don't get rezzed or just stay by the entrance.
5. Group does the three desrt missions, Elona's Reach, Thirsty River, and Dunes of Despair.
6. Group runs to Augury Rock.
7. You will be about level 3 by this time, talk to the sage and get him to open the mission.
8. Beat your mirror self, instant level 20!
To beat your mirror you can either bring skills that will hurt him for attacking like Empathy or Price of Failure. Also, skils like Retribution that return damage to him plus HoT (Healing Breeze) can work but bring Scourge Healing and Heal Party but don't use Heal Party. Make sure that you set you attributes to maximize the damage he does to himself.
Once you enter the mountain, skip the cinematic, if you want to see it you can watch it and then try, but the extra time from skipping helps so if you don't beat him the first time try that. Then turn 180 degrees toward the opening. Move in that direction until you can go up on one of the ramps along the wall. I, normally use the left one but either should work fine. Cast Empathy or Price of Failure etc on the mirror and then move up the ramp to give your self a little distance. Don't move too far or he will try and follow, you want him below you at all times. Once he starts attacking (he will use a bow no matter what you use or have skills in) watch him draw back the bow and wait about 1/2 a second and then move sideways. This will cause you to dodge the arrow while he takes damage from Empathy or Price of Failure. If you have a blind skill it also works well with PoF or Empathy and you don't have to dodge but don't bring any condition removal. Once you do it a few times you will get the timing of dodging his arrows and it gets to be pretty easy. I beat him with a level 15 in less than a minute You can also just dodge his arrow and use a newbie wand to kill him but that takes ~10 minutes and a lot more arrow dodges.
Here is a thread, with pictures, that documents someone doing this as a level 3:
