There should also be an appropriate balance between these two essay components. Most students make the mistake of writing too much knowledge and not enough evaluation (which is the difficult bit).
It is best to structure your essay according to key themes.
Themes are illustrated and developed through a number of points (supported by evidence).
Choose relevant points only, ones that most reveal the theme or help to make a convincing and interesting argument.
Rather than hunting for weaknesses in every study; only highlight limitations which make you doubt the conclusions that the authors have drawn – e.g.
where an alternative explanation might be equally likely because something hasn’t been adequately controlled.
Instead make sure you expand on your points, remember, quality of evaluation is most important than quantity.
When you are writing an evaluation paragraph use the PEC system.
(Point) It is argued that psychoanalytic therapy is only of benefit to an articulate, intelligent, affluent minority.
(Explain) Because psychoanalytic therapy involves talking and gaining insight, and is costly and time-consuming, it is argued that it is only of benefit to an articulate, intelligent, affluent minority.