You can put up banners on your site, to promote your affiliate offers. Most affiliate programs will usually provide their own creatives when you sign up for their offers. All you have to do is insert the banner on a highly trafficked page (your affiliate tracking is usually embedded within the code). Banner ads in the right locations can do a great job of driving sales.
Freelancing has always been a popular way to earn money online and the Internet has a plethora of options. There are several websites offering freelance tasks for people with varying skills. All you need to do is to create your account, browse through the listings, and apply for the task that suits you. Some websites may even require you to create a personal listing with the details of your skillset, so that interested clients can contact you directly. Outfiverr.com, upwork.com, freelancer.com, and worknhire.com are some websites that provide freelance jobs. You can earn anywhere between $5 and $100 through these websites.
You'll also need ecommerce software, fulfillment software, worry about warehousing, customer service, refunds and so on. But that's not all. You'll also need traffic. Think search engine optimization, Facebook ads, and other social media campaigns. Sound like a lot of work? Sure, it is. Especially if you do it all on your own. You could opt for Amazon's platform, which might be the easier route. But, then again, at the end of the day, this is a serious business, which could produce significant profits. So you're either all in or you're not.