Surface mail is a fairly inexpensive way to get stuff to Ghana. Do not send boxes via airline cargo because duty is charged in Ghana. Sending anything by surface mail is at your own cost and risk. Your luggage will get tossed around unmercifully so pick out sturdy bags - tough canvas or nylon. All bags should lock securely to be sure your things get safely to and through the Accra airport.
Suitcases are hard to travel with.
Put leaky things in zip locks or when possible, Tupperware. An extra supply of zip-locks will prove invaluable. Pack valuables in your carry-on luggage en route to Accra, especially irreplaceable documents. If nothing changes, you will arrive in the rainy, high humidity season. Hand washing becomes very hard on your clothes, so pack durable clothing.