Do a Google search for “economy of x” the first organic result will usually be the Wikipedia page of that country’s economy, scroll down to its infobox and look for some key metrics:
Look at its trade deficit
A trade deficit is an economic measure of international trade in which a country’s imports exceeds its exports. A trade deficit represents an outflow of domestic currency to foreign markets. A trade deficit typically occurs when a country does not produce enough goods for its residents (or in the case of places like the Maldives for its tourists).
Look at existing import countries
Is South Africa already large exporter to that country? There’s usually a good reason for this. Location (Mauritius being a good example), quality of certain goods and price (global trade is usually done in US dollars, this means south Africa can undercut many other countries as it conducts domestic business in ZAR). This also means that the country is used to doing business with South African companies, there would be lots of people in South Africa experienced in doing business with that country, its laws and customs process etc. This also opens the door to pitch to companies in that country, find out if they are happy with their existing South African suppliers, its quality and prices etc.
Look at trade agreements
While there may not currently be a lot of trade between South Africa and a foreign country, there might be trade agreements in place to stimulate more trade between two the two countries, look what they are and what they cover.
Sanctions-busting (not really)
There are countries under US and EU sanctions that opens up opportunities for South African companies. The South African government usually sides with China and Russia in international matters meaning it often does not recognize a sanction placed on a country by a Western government. As a South African resident you are not subject to US or EU laws as you don’t live under their jurisdiction. Companies in these countries will be eager to do business considering that it can’t do business with companies in with sanctions against it. It might even open the door for countertrade: instead of paying for Persian carpets from Iran in US dollar, exchange it for local goods that you paid for in rands.
Find your own niche
There are lots of opportunities out there, but you can’t always do it from your computer, you need to establish contacts, attend local trade shows like those held at the Cape Town International Conventional Centre, if you can afford to visit other countries, reach out to friends who have emigrated etc.
There are various techniques one can use to find overseas markets for South African products as well as strategies: do you enter existing markets or create new? Do you position yourself as a cheaper US or European equivalent? Or do you fill the gap left by international sanctions (which South Africa does not recognize)?