Even though the North AND South deserts of Ro (FYI Ro is a full part of the name if you didnt know) are level 20 hot zones, after about level 23 there are very few things that will give you much exp.(there still is, but they are kind of hard to find) so I wouldnt wast my time there. Hope this helps =)

When you start a human character and you might start out in Qeynos, kill creatures in North Qeynos until your level 5.



You could go to Qeynos Hills until your lvl 10 or go to Crushbone which is a very popular zone for low level characters to get experience.



Once you get level 15 or so, maybe form a group with other characters and go to Paludal Caverns until level 25.



Hope the strategy works for ya.