More precise analytic expressions for ferromagnetic resonance of single crystals are calculated, the approximation being carried to terms quadratic in the magneto-crystalline anisotropy field. On the basis of these, the problem of the compensation of the temperature instabilities of single crystal YIG microwave devices, caused by the variations of the anisotropy field, is discussed. Significant corrections to the temperature compensation directions that have been in use are introduced. Formulae for the calculation of the temperature characteristics of YIG devices with the applied magnetic field in the corrected compensation directions are given.