Methods for evaluating activation energies and escape frequency factors from glow curves by the use of various heating rates are discussed. For first-order peaks, the method of finding the glow parameters by measuring the shift of the maximum temperature with changing heating rate is generalized. This method, known to be true for linear and exponential heating rates, is shown in the present paper to hold true for any monotonically increasing heating function. The method using the variations in the maximum intensity with changing heating rates, previously known to apply for certain thermally stimulated current peaks is proved to be true for all first-order peaks. Analogous methods are found for general-order peaks, an important special case of which are the second-order peaks. Computer calculations as well as experimental results in ZnS:Er3+ samples are given as a check. These methods are of special value when the peaks are not "clean" since the quantities used are measured only at the maximum point.