Emails and Direct Mail,usually difficult for most to believe. Bought every book I could on the subject of selling and embraced the gift. Over a period of time I've become rather good at the content creation, the email funnels, the service packaging and of course the customer experience improvement. I am an Experience Designer, I focus on Design of Utility Products, Customer Engagement, Growth Hacking and Customer Experience.
The Secret behind it all is a mind shift change. Focus on making your clients' money, that will get you paid very well especially when they make money.