In purely practical terms, the most profitable online business to look at is selling goods. Online shopping has exploded and it continues to expand, to the extent that major retail companies are alarmed and striving to get their presence online ASAP.
For someone looking for fast results I would suggest opening an Amazon FBA account, sourcing good quality products after researching extensively, and presenting these on the Amazon platform, it is just huge, and extremely profitable.
For any venture to be successful, you have to offer a product or service that consumers desire greater than the money they have to pay for your product or service. Once you discover that, you will operate a successful e-business.
Ebrima - I can think of few resources you can use. (1) Shirley Tan's book : Ecom Hell: How to Make Money in Ecommerce Without Getting Burned (http://www.amazon.com/Ecom-Hell-Ecommerce-Without-Getting/dp/0615786871/ref=la_B00DPDC7B4_1_1?s=books&ie=UTF8&qid=1396486528&sr=1-1) and (2) http://www.ecommerceuncovered.com/not-sure-where-to-start. - When you have built your business and ready to exit - I can help :)