It's easier than you think getting started selling online, as you don't have to start with your own product.  By using affiliate marketing strategies you can started very quickly, with minimum time investment.
You will basically be acting as a middle man.  You will capture potential customers using maybe social media, or SEO to get them to your new site, and then you will direct them to the product site.
Technology enables you to use some simple coding in the URL that you use to send them to the affiliate site to make sure you get paid the commission on any purchases they make.
You might want to use some pre-selling tactics in order to create 'warm' potential buyers.  It's not all hard sell on the internet.  It's more about building relationships, and of course, trust.
One great way to gain the trust and interest of visitors to your site is to offer them something for free, in return for them providing you with their name and email address.  Build confidence in them by firstly explaining that you will never pass their details on to a third party (and please, stick to that rule guys!) and secondly make sure that what you offer them for free has some real value.  A quality ebook for example with some sound tips in it.
Once you have your visitor's details, keep in touch with them regularly, and continue to build the relationship and trust.
Try to resist constantly selling to them, as this will drive them away.  Instead, give them value in your emails to them.  Offer them free ebooks, information and valuable tips.  Then you can scatter a few sales promotions in from time to time that will be much better received.