Students have problems with understanding, using and interpreting graphs. In order to improve the students' skills for working with graphs, we propose Manual Video Measurement (MVM). In this paper, the MVM method is explained and its accuracy is tested. The comparison with the standardized video data software shows that its accuracy is comparable with the one of the standardized video data software, which enables it for use in physics education. Posttest conducted after the lecture with software for video measurement shows slight improvement in understanding graphs. The students were asked at the interviews to explain the answers they have given at the test. The performance was poor. The interviews conducted one month after the lecture with MVM show big improvement in students' understanding position-time graphs, higher skills for collecting data and their interpreting. In addition, the vocabulary used to explain the answers was more precise and the use of physical quantities is more correct. Despite this fact, the students still do not understand velocity-time graphs still.