Although West Africa is changing, social mores remain conservative. Most locals don't expect you to know all of the rules and will forgive any faux pas. Even so, please keep in mind the following guidelines:
Attitude If you're in a frustrating situation, be patient, friendly and considerate. A confrontational attitude can easily inflame the situation (especially when dealing with police officers and immigration officials) and offend local sensibilities.
Islam Be respectful of Islamic traditions and don't wear revealing clothing; loose, lightweight clothing is preferable.
PDAs Public displays of affection are usually inappropriate, especially in Muslim areas.
Photography Always ask permission to photograph people.
Conversation topics Avoid vocal criticism of the government or country; the former could get your friends in trouble and many West Africans take the latter personally.