1) Deported people to Siberia( for example from the Baltic states in june of 1941 and in march of 1949), they were often taken to the labour camps or killed, or they just died on the way to Siberia.
Effect: People died, most people deported were the wealthy and educated people, therefore countries were left with the uneducated.
2) The collectivisation - the grouping together of farms to be owned by the state.
Effect: Massive fammine and poverty since the state took almost everything producted and only a small amount of the production was left for the people.
3) There was no freedom of speech. Propoganda.