What is the best way to get started in this dive?
The first step is to… find good resources that show all of the countries in Africa.  We will provide all of these resources for you on the sections that follow.  
Once you get that, start counting.  You need to clearly know how many countries are in Africa.  Once you have that memorized, you can use that as a tool to help you memorize and remember them all.
Next, write them all down.  Try alphabetical order for starters, if that helps, or try doing so by creating a mental image of where each country is in relation to its neighbors.  Be sure to keep testing yourself by writing them down, or saying them out loud while using your fingers to count as you speak.
What are you waiting for?  Let’s do it!