I've been selling on marketplaces such as Amazon/eBay since 2000. Each marketplace must have a different strategy. Marketplaces can also be looked at customer acquisition channels for your brand. Having a website is crucial and must be part of your long term strategy.

I always say this.....Marketplaces sales are like one night stands and sales on your website are more like long term relationships. The lifetime value of a customer should be the ultimate goal.