
First, develop your love in selling. You cant' be good to something you do not love. Talk to topnotch seller, read books about selling, and get into selling.
Second, chose product to sell. There are a lot of product in the market today, and there are a lot of customer looking for a product they need. Chose a product you know well, probably a product that you're already using, get familiar with the benefits and advantages of that product, a product that will make you proud to present it, and confidently can recommend it to others.