Just because you're a Ranger, doesn't mean you can only fight Worms. =P
For now, you might be best off heading to Highlands or Dangruf Wadi and beating up on Saplings or Wasps / Goblins. Once you get to 11 or so, move into Valkrum, then down to Korroloka (worms!) at Lv16. Korroloka has always been my favorite xp spot, and I hope you have the same success down there that I did. At Lv20, of course, you'll need to move to Qufim and fight more Worms. =)
Hope some of this helps!