You just need to get rid of the subsistence farms and turn the peasants into laborers etc. If your country has a strong landowner class or clergy then it seems like worth it to empower the industrialists and the middle class through laws to speed up the process. What you want in the end is a strong intelligentsia and unions, they should just become communists over time on their own. Country folk can be helpful at the start (they were for me the first to form a communist party), but become reactionaries pretty soon. The middle class does become fascist at some point in the process, but I haven't seen them cause any problems.