Before traveling to Saudi Arabia, find out everything that needs to be known about the country's culture, religion, and customs. There a number of websites as well as downloadable journals or publications that can be browsed on the internet. It would be wise to learn a few arabic now and then especially their formal greeting: "Assalam Aliakom"which means "peace be with" you in english. The proper response to the formal greeting would be "Allaikom Salam" which means "and peace be with you too". Use this form of greeting any time of the day.
When traveling to Saudi Arabia, most probably one would not meet a Saudi directly. Take note that there about 8 million expatriate workers here and most of the time general Engrish (not English) is being used. If one does have the chance to meet a Saudi directly, observe some very simple etiqutte and manners most especially business etiquette.
Tips are generally accepted in hotels and restaurants.When giving tips, it generally would not matter how much.
Here are some rules not found in other sites:
Never make an "O" sign with the hand and fingers as this is misconstrued as something else. For some westerners, an "O" sign would mean money. To the Saudis, its taboo as it symbolizes a woman's dignity.
Taking pictures of women and children are generally not allowed. Always ask permission first.
Never offer help or rush to the scene of a female in distress, most especially in emergency medical cases. Only medical staffs are permitted to approach a female patient.
Women are not allowed to drive. If you are a westerner and you want to drive, you must bring a male companion and expect some curious public eyes.
Never use your finger to point at anyone even if you are engaged in a heated argument with someone.
Always use your right hand. If you are left-handed, use the right hand in formal settings as much as possible.