The memory conformity effect occurs when people witness a given incident (e.g. a crime) then talk to each other about it, and the statement of one person affects the memory account of the other person with respect to this incident. The aim of this article is to improve the quality of witness testimony by verifying the effectiveness of three methods that aim to reduce memory conformity effect: (1) an extended warning against misinformation; (2) a method based on information about memory functioning and its fallibility and (3) a method consisting in motivating participants to resist influence and demonstrating their individual vulnerability to it. In the presented experiment, the innovative MORI technique was used to study the memory conformity effect. This technique allows a pair of participants to sit beside each other, look at the same screen and see a different version of the same criminal event. In the next stages, the subjects are asked to answer a series of questions about different details, thereby introducing mutual misinformation; then, the participants perform an individual memory test. In the experimental conditions, this test was preceded by one of the three tested methods in each group, with the aim of determining their effectiveness in reducing memory conformity. It turns out that the implementation of an extended warning against misinformation eliminated the memory conformity effect, while the application of two other methods led to a reduction (but not complete elimination) of the studied phenomenon.