Just join a PT at that level. You should be getting 200+ XP and chaining IT worms easily. It will be ~at least~ twice as fast leveling that way than solo. The have nerfed the the run in/shoot, run out of magic range, worm technique RNG's were able to use before. Another idea is get a WHM or RDM and PT only with them and have them heal while you shoot away.
Misha Mithra 50 RNG/NIN
50RNG/31WHM/25WAR/25NIN/15RDM/43THF/12BLM all jobs 5+
I dont care how tough, l33t, or whatever geek-*** term you call yourself online...I can STILL kick your *** in real life fool.