Online marketing is about demonstrating and packaging your product in a particular way that will land a sale
. This will help your prospect's gain confidence in you and add to your sales. There are a number of things that go into it, directly from the way your build your website to the product graphics you utilize. You need to focus on all these elements that make it easy for your potential customers to trust your product. Make sure to use a "money back guarantee" to highlight your item's usefulness and make the prospect take a move.
All in all, marketing online is no different than marketing offline. Common sense is the number one factor in making sure nothing goes badly.