If you're headed into the city of Accra then you'll have little trouble as the airport is situated close to the the city centre. If you're heading into other parts of the country or more inland, then your options will include air in addition to road. I want to get to Kotoka
Kotoka is situated in the Airport City of Accra and as such within walking distance to great eating places, shopping and retail areas and places to stay. If you're traveling light and feel up to to it, you're more than welcome to walk out of the airport at anytime
Hail a taxi
You'll find good and safe links with local taxis and app-based (such as Uber) out of the airport. Taxis are available from just outside the Arrival Halls.
Note: Do always negotiate your fare before boarding, when using local unmetered taxis.
Drive / Rent a car
If you're getting picked up or exiting the airport in your own car, you'll have no problem at all as there are great parking facilities and exit routes out of the airport. Just follow the exit signs from any of the car parks. Head towards National Highway, N1, if heading east or west or take the N2 if you're going up north of the country or out of the capital. (The N1 will connect you to any part of the country). Alternatively, you can choose to hire a car instead from hire companies outside the Arrival Halls.
Note: The airport drive out can get busy and may have long traffic tail-backs during peak hours.