There are two main ways to find employment in Ghana. The first one, and the best one for expats, is to be recruited outside Ghana, as then you are assured an expat salary and all the perks such as airfares, accomm, medical etc. To find these jobs you need to look on websites which list jobs in Ghana.
A second way is to come on a tourist visa and network and hope you will find an employer. This is a bit more risky as you might find yourself hired as a local on a local salary with none of the benefits.
Accommodation is expensive in Ghana if you want to live in a modern house in an expat area. You might be able to share accommodation but it will cost $US 500+