Dropbox successfully moved upmarket and secured big enterprise customers by building features such as admin controls and integrations that made their product more appealing to these larger companies. The land-and-expand strategy, which involves selling to developers and business users first before targeting IT administrators, was key to this success. However, the development of enterprise-ready features like authentication, access controls, audit trails, and compliance with industry standards was crucial in enabling Dropbox to close deals with major enterprises.