I made mention already of an exercise that myself and Charlotte came up with to help developers to think in terms of granular components: using a humble pair of scissors to cut up screenshots or mockups into their constituent parts.
Recently we repeated and added to this exercise. Once the groups of components are gathered together—buttons, form elements, icons, whatever—we go through each group. Everyone writes on a post-it what name they would give this component—button, formField, icon, etc. Then everyone slaps down their post-it notes at the same time. See any overlap? That’s your class name.