Not to brag or something, but I consider myself highly skillful and adroit when it comes to marketing and selling stuff online. For some reason, I might not be quite good when it comes to selling stuff offline or maybe I will be, I just haven't tried it yet. But to talk about online selling, I am really skilled. In my personal opinion, the only skill required for effectively selling a product online is the writing skill. If you can write a really good article about the pros and cons of the product and as a matter of fact, if you can write a fascinating article about the complete review of your product, then people are definitely going to buy your product. When it comes to selling things online, the word of mouth is not essentially the best strategy to be adopted. All you need is to write a great article about the product and publish it the article directories, blog directories, social networks and stuff, you will automatically start to get a couple of sales every hour. Another important thing that you have to keep in mind is that you should never rush for promoting products which will earn you more commissions. Stick to promoting products which you like personally. Promote products which are more useful. Stuff that general public will feel inclined to. I hope this helps.