If you're serious about marketing anything online, rather than opting for running ads on your blog (which won't make you real money unless you have at least hundreds of thousands of visitors per day) or engaging in affiliate marketing, you should build a topical lead magnet that will sell a digital product or offer that you create in the back-end. The lead magnet will entice people to sign up to your list and provide you with their email address.
My name is Jamie Spencer and I have spent the past 5 years building money making blogs. After growing tired of the 9-5, commuting and never seeing my family I decided that I wanted to make some changes and launched my first blog. Since then I have launched lots of successful niche blogs and after selling my survivalist blog I decided to teach other people how to do the same.
Lets say, for example, that you refurbish and resell used smartphones out of your home. You could use a blog to attract visitors to your website where you list your current phones for sale. Your blog might cover topics about DIY refurbishing. On one level, it seems counterintuitive because you want people to buy your phones, but it also helps you build a brand and gain recognition. Social media guru Jay Baer explains the concept on Copyblogger: