Procedures to measure critical parameters such as the critical temperature, Tc, the upper critical field, Hc2, the critical current, Ic, and the AC loss in practical superconductors are described. The criteria and factors which influence the evaluation of the parameters are briefly discussed. The importance of the holder in the 4 probe method which supports the sample against the Lorentz force is emphasized from the view point of strain effect. The magnetization method to measure the AC loss of a multifilamentary wire is described in detail.