A seller needs to be competitive to sell products on Amazon marketplace. As there are many sellers selling same or similar products with different quality and price, a seller needs to work on many fronts. Some of these include acquiring better quality at cheaper price. Selling at lower selling price. Reducing costs at seller end. Better product images and better detail page. Selling as pack is also cost effective as shipping would be low for multiple items. Using advertisements, coupons and promotions. Getting reviews and ratings.