I try to set our theories and it's associated research onto 1-2 pages then colour code it as to whether it supports/refutes it. For some of the more difficult things I try to make up rhymes to remember the names or associate the researcher with a picture each time I revise their research. And remember that you don't have to know every study for every theory, just enough to write about in the essay so pick the most memorable ones.
I try to set our theories and it's associated research onto 1-2 pages then colour code it as to whether it supports/refutes it. For some of the more difficult things I try to make up rhymes to remember the names or associate the researcher with a picture each time I revise their research. And remember that you don't have to know every study for every theory, just enough to write about in the essay so pick the most memorable ones.