Since the sun is very intense, you may need to vary sleeve lengths until you get into condition. Remember that loose clothing is more comfortable than close fitting, and that synthetic fibers tend to be hot. Shorts are not recommended because of Arab customs. This would be offensive to them. Your work clothes will get so dirty that you will likely trash them at the end of the program.
Socks take the worst beating.
White socks will turn brown, or worse, by the end of the season. Some students like to wear bandannas for protection from dust on the tell. You will do considerable kneeling, generally from four to six hours a day in a square, so you might want to consider knee pads, which you can find in any Home Depot or garden center. You will do well to find your work clothes at a Good Will or Salvation Army store. These are essential even for those with the toughest hands.