Handshaking is the usual mode of greeting, usually accompanied by a light touching of the shoulders. For friends or families it is common to kiss each other on each cheek. The greeting is usually accompanied by a pleasant discussion before getting down to business. Tea or coffee is often offered and time is not that important. Display of sexual intimacy, like kissing or hugging, will arouse embarrassment among most Ethiopians.
Clothing will depend on the time of the year you visit and the planned activities, but most of the time the temperature is mild, between 15-25° C. Travelers should bring light, summer clothing for the daytime and something warm, like a sweater or jacket, for the evenings. Although temperatures are not very high, the sun is strong and people coming pale and pasty from a European winter should be careful of sunburn - long sleeves, sunglasses and a hat are advisable.
For trekkers in the Simien or Bale Mountain warm clothing and waterproofs are a must, as the temperature drops quite rapidly towards sunset. A 3-4 season sleeping bag (which will be provided) is necessary. Keep in mind that sandals, as most Ethiopians wear, will not provide protection against stones or thorns. Also unpaved roads turn into muddy paths after rain, so light but strong walking shoes are recommended.Visitors, who are not trekking or coming during the rainy season, don't need to bring special rain wear.
Whether Christian or Muslim, most Ethiopians tend to dress modestly, so shorts and skimpy tops should be avoided for either sex (unless at the beach, lakes or at the swimming pool). Shorts and tank tops would strike most Ethiopians as underwear, and while it is unlikely that any one would say anything, attempting to go into any religious site "underdressed" would cause offense. On the other hand before entering a church or mosque, visitors should remove their shoes.
Be sensitive about intrusive photography and ask for permission before taking photographs of people. Generally there is no objection, but in some areas, particularly among nomads, among the Afar and in the Omo Valley, people will often ask for money. Photography in churches is allowed, but there is often a charge for video photography. There are laws and regulations about taking photographs in sensitive areas like airports and around military camps.
Smoking is not popular amongst Ethiopian people and should not be done in front of priests.