  Motivated by a recent paper by Rychkov-Tan \cite{Rychkov:2015naa}, we
calculate the anomalous dimensions of the composite operators at the leading
order in various models including a $\phi^3$-theory in $(6-\epsilon)$
dimensions. The method presented here relies only on the classical equation of
motion and the conformal symmetry. In case that only the leading expressions of
the critical exponents are of interest, it is sufficient to reduce the
multiplet recombination discussed in \cite{Rychkov:2015naa} to the classical
equation of motion. We claim that in many cases the use of the classical
equations of motion and the CFT constraint on two- and three-point functions
completely determine the leading behavior of the anomalous dimensions at the
Wilson-Fisher fixed point without any input of the Feynman diagrammatic
calculation. The method developed here is closely related to the one presented
in \cite{Rychkov:2015naa} but based on a more perturbative point of view.
