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.
White clothing tends to get dirty and stain fast.
Ghanaians are very meticulous about their dress in the work place and wear their good clothes. Cleanliness is a sign of respect. Shorts are acceptable around your house or community after work, but are not worn in public. Besides, they are not practical, comfortable or appropriate when traveling in a crowded bus. You could only wear these at the beach.