Second, consider that country's position on land conservation. A preserve, park or conservation area may be defined differently from country to country. Depending on time and budget, you may need to make a choice between the two. Decide if remote and undeveloped or easily accessible is more important to you. In some countries, the safari location may be far from the nearest city, and that might determine your plans.
Some countries also specialize in certain types of safaris.
For example, you can't see the Wildebeest Migration in Liberia, but you can in Tanzania. It used to be that going on safari necessarily meant seeking out large game like rhinoceros, elephant, giraffe, and lions. Big game safaris are still the most popular, but if you have a special interest, there may be a safari to accommodate you. There are safaris that focus specifically on birds, for example. If you want to see a particular animal, perhaps the fanged, hooked, primitive chevrotain, you might choose a safari in Liberia, where the chevrotain still roams free inside Sapo Park.