Entry
Your passport decides the visa rules, so see the official site below. Anyone who needs a visa should apply well ahead through a Senegalese embassy. Documents usually asked for are a yellow fever certificate, proof of accommodation, a return ticket, photos and a passport with 6 months of validity; an entry authorisation may also be required. An embassy, or the Senegalese foreign ministry, can confirm the rule as it stands now, so ask before booking. A doctor can advise on malaria prevention.
Culture and practical - take note
Over 90% of Senegal's people are Muslim, and the country is famous for 'teranga', meaning warm hospitality. Take care to greet people properly, enquiring about their families, and use the right hand. Modest dress matters most away from tourist beaches. The main day of prayer is Friday. Halal food can be found everywhere. Persistent sellers are to be expected in markets and on beaches, and a polite 'no merci' does the job. Photographing people calls for asking first. Make sure you hold copies of your passport, and do not walk alone after dark. Atlantic currents are strong, so enter the water only at safe spots. Gor茅e Island serves as a memorial to the slave trade, so be respectful there. Some governments advise caution around Casamance and along the borders, so check advisories. People speak French and Wolof.