Marx predicted that capitalism would collapse under its own inconsitencies and that would cause a revolution in which the workers would take hold of the means of production. When this didn’t happen, other strategies were used, like using a revolutionary vanguard to grasp power in a coup and force socialism on society. Another tactic is using a emotional subject to create revolutionary agitation. Originally the suffering of the working class could be used, but when the workers got more salary, a yearly holiday and other amenities of modern life, they switched to other groups, like women, migrants, ethnic or sexual minorities. If they are not available in your own country or if they are not disgruntled enough, you can always use groups from abroad. These groups are used to get concessions, money or jobs from gentle institutions like universities.