Epithelial cardiac progenitor cells of the second heart field (SHF) contribute to growth of the vertebrate heart tube by progressive addition of cells from the dorsal pericardial wall to the cardiac poles. Perturbation of SHF development, including defects in apicobasal or planar polarity, results in shortening of the heart tube and a spectrum of congenital heart defects. Here, we provide detailed protocols for fixed section and wholemount immunofluorescence and live imaging approaches to studying the epithelial properties of cardiac progenitors in the dorsal pericardial wall during mouse heart development. Whole-embryo culture and electroporation methods are also presented, allowing for pharmacological and genetic perturbation of SHF development, as well as image analysis approaches to quantify cell features across the progenitor cell epithelium. These protocols are broadly applicable to the study of epithelia in the early embryo.