(make sure that you specify West Africa, sometimes mail gets sent to Thailand(?) by mistake
2) use a bubble envelope (because packages are more likely to get stolen)
3) be sure to write Air Mail/ Par Avion on it
4) put anything that has the remotest possibility of exploding in ziplock baggies.. especially all food!
5) Write that the package has no (or very very little) value on the customs form.. and say it is something boring (books) so it won't get stolen. Some people recommend writing that it is religious materials.