Learning medical gestures requires regular hands-on training to acquire the dexterity needed to perform them without injuring patients. For obvious ethical reasons, this training cannot be carried out directly on the patient. In this context, the use of cadavers has long been the preferred method of training, despite the difficulty of obtaining them and the fact that cadavers deteriorate rapidly. For several years, technologies have led to the development of medical training simulators that combine a numerical simulation (reproducing the organs' behavior during the gesture) with haptic devices (reproducing tactile sensations). As designers of several haptic training simulators, we aim to impart our expertise by detailing in this paper an empirical design methodology for the development of such simulators.