Cardiovascular clinical trials continue to under-represent children, older adults, females and people from ethnic minority groups relative to population disease distribution. Here we describe strategies to foster trial representativeness, with proposed actions at the levels of trial funding, design, conduct and dissemination. In particular, trial representativeness may be increased through broad recruitment strategies and site selection criteria that reflect the diversity of patients in the catchment area, as well as limiting unjustified exclusion criteria and using pragmatic designs that minimize research burden on patients (including embedded and decentralized trials). Trial communications ought to be culturally appropriate; engaging diverse people with lived experience in the co-design of some trial elements may foster this. The demographics of trialists themselves are associated with participant demographics; therefore, trial leadership must be actively diversified. Funding bodies and journals increasingly require the reporting of sociodemographic characteristics of trial participants, and regulatory bodies now provide guidance on increasing trial diversity; these steps may increase the momentum towards change. Although this Perspective focuses on the cardiovascular trial context, many of these strategies could be applied to other fields.