An attempt is made to go beyond the framework of conventional weak turbulence theory. A simple dispersion equation for the stability of a steady turbulent state can be found by selective summation of higher‐order terms from perturbation theory. The main contribution in the model to be considered here comes from particle motion in the turbulent electric field. In the limit of small wave amplitude, the usual equations of the weakly turbulent plasma can be obtained easily. The theory is applied to the drift‐cyclotron instability of a nonuniform plasma to find the steady‐state level of drift‐cyclotron turbulence. The growth rate of the instability changes essentially at the nonlinear stage, so the usual dimensional arguments to find the turbulent diffusion coefficient cannot be applied using the linear description only.