Visas. Citizens of most Commonwealth countries, the EU, and the US do not need a visa for stays up to 90 days. You will get a stamp on arrival. Your passport must be valid for at least six months. Check current requirements before travel -- rules do change.
Money. The currency is the Botswana Pula (BWP). ATMs are widely available in Gaborone, Maun, Francistown, and other towns. Visa and Mastercard are accepted at hotels, lodges, and larger shops. In rural areas and smaller towns, carry cash. South African Rand is widely accepted, especially in the south. Safari lodges typically quote and prefer payment in US dollars. Tipping is appreciated but not compulsory -- 10% at restaurants and P50-100 per day for safari guides is standard.
Language. English is the official language and is widely spoken, especially in towns and the tourism industry. Setswana is the national language and the mother tongue of most Batswana. A few words of Setswana go a long way -- "Dumela" (hello) and "Ke a leboga" (thank you) will earn you smiles.
Safety. Botswana is one of the safest countries in Africa. Violent crime against tourists is rare. Petty theft occurs in Gaborone as in any city -- take normal precautions. The real dangers are on the roads (animals crossing, long distances, drowsy driving) and in the bush (wildlife, dehydration, getting stuck in sand). Do not approach elephants, hippos, or buffalo on foot.
Health. Malaria is present in the north (Okavango, Chobe, Makgadikgadi) especially during the wet season. Take prophylaxis and use repellent. The south, including Gaborone, is low-risk. Tap water in towns is safe to drink. In the bush, carry purification tablets. Medical facilities in Gaborone are adequate; elsewhere they are limited. Travel insurance with medical evacuation cover is essential.
Electricity. 230V, 50Hz. South African-style three-pin plugs (Type M). Bring an adaptor.