This article describes the know-how and the procedures for measuring displacements and strains using digital image correlation. The procedure for creating random pattern on specimen surface, not only ordinarily size pattern, but fine pattern for microscopic measurement and coarse pattern for infrastructure is described. The adjustment of optical system for imaging such as the F-number related to the resolution and the depth of field of optical system is shown. In addition, the impacts of the data processing parameter such as the subset size, the subset shape function, and the window size for obtaining strains on the measurement results are described. The accurate and precise measurement is expected by the measurement procedure described in this article.