The biggest advice I can give is to pick a small niche, set up a site and start experimenting. Make mistakes and learn from them. That’s the only way you are going to succeed. Of course, have realistic expectations. It took me more than 1-2 years to start making decent money. But the beauty of it is that once you make that first dollar, you know it works and at that point it just becomes a matter of scaling it up, working harder and smarter to scale up your business.
If you're interested in online marketing, setup email software and create a lead magnet that you can use in your sales funnel. Then, build up that list. It's often said that you can expect to earn about $1 per subscriber per month. If you have a list of 10,000 subscribers, that means you can earn roughly around $10,000 per month. You will need to deliver value and not pitch them on every email, but it is a very achievable goal in a short period.
Dayo, sadly, because of the market size, app related business remain only profitable in a few western countries. I don’t know of any that could be used in Nigeria. That said, you can always put your own twist on things and make something that people in your local area could find useful. Essentially, you create a niche market out of it, and that can be very profitable.
If you’re a skilled worker in a specific niche, like marketing, design, or software development, there are specialty marketplaces that cater just to you. These are amazing places to make money online as you know that the people visiting them are looking specifically for the skills you have. Check out places like 99Designs or Dribbble for designers, Cloudpeeps for marketing and SEO professionals, and TopTal, Crew, or Gigster for high-level software developers. Once you've built up your development skills, you can begin building a brand for yourself as a higher-value consultant and start charging brands for larger projects like implementing an entire WordPress security overhaul or migrating a website from http to https.
Then, if my piece of content is so unique and valuable around hiking backpack recommendations, that other reputable outdoor websites are willing to link to it and build the page’s authority, then I’d have a very real opportunity to rank high in organic search for these search terms (meaning, my page will come up first when someone searches for hiking backpacks).
Last but not least, you can also earn money online by building an online community, although the monetization strategies you can pursue will vary a lot depending on your goals. You can build a community with a blog, for example. You can also build an online forum and charge people for membership. You could even build up a Facebook group and use your influence there to sell and promote products.
One of the cool things about Google AdSense is that it's so easy to get set up. If you have a blog or website, you can sign up for a free Google AdSense Account. From there, Google will give you a unique code that you will paste onto your website. Google takes it from there, tracking your page views, traffic, and earnings on your behalf. There is no upkeep or maintenance to get this thing going, which makes it a no-brainer if you have a website already.