Spectral analysis of hot stars requires adequate model atmospheres, which take into account the effects of non-LTE and radiation-driven winds properly. Here we present significant improvements of our approach in constructing detailed atmospheric models and synthetic spectra for O-type stars (model code wm-basic; see Pauldrach, Hoffmann & Lennon 2001). The most important ingredients of these models with regard to a realistic description of stationary winds are: (i) a rigorous treatment of line blocking and blanketing; (ii) a consistent determination of the radiative line acceleration; (iii) a considerably improved and enhanced atomic data archive providing the basis for a detailed multilevel non-LTE treatment and an adequate representation of the radiative line driving; and (iv) the inclusion of EUV and X-ray radiation produced by cooling zones originating from shock-heated matter. This new tool not only allows to constrain the properties of stellar winds, the stellar parameters, and the abundances via a comparison of observed and synthetic spectra, but also provides the astrophysically important information about the ionizing fluxes of these stars. We use this new method to compute selfconsistent wind parameters for a series of Galactic stars analyzed in the optical and verify the theoretically predicted dependence of the wind momentum on metallicity.