Buy at least a mosquito net preferably permethrin-impregnated and a good repellent preferably DEET-based. Permethrin that can be washed into clothing and will remain in the garment for a month before the effectiveness of the product wears off and should be reapplied.
vaccines
A yellow fever vaccine is required and proof to enter the country. It is, however, not checked on a regular basis.
maps
Tourist maps are available at the tourist offices see au-senegal.com for that one.
international driving permit (idp)
If you want to explore the country by rented car, you need one.