  We present two variants of an approach for evaluation of observables in
analytic QCD models. The approach is motivated by the skeleton expansion in a
certain class of schemes. We then evaluate the Adler function at low energies
in one variant of this approach, in various analytic QCD models for the
coupling parameter, and compare with perturbative QCD predictions and the
experimental results. We introduce two analytic QCD models for the coupling
parameter which reproduce the measured value of the semihadronic tau decay
ratio. Further, we evaluate the Bjorken polarized sum rule at low energies in
both variants of the evaluation approach, using for the coupling parameter the
analytic QCD model of Shirkov and Solovtsov, and compare with values obtained
by the evaluation approach of Milton et al. and Shirkov.
