  We discuss the general structure of effective hamiltonians for systematic 1/N
expansion in QCD using the light-cone quantization. These are second-quantized
hamiltonians acting on the Fock space of mesons and glueballs defined by the
solution of the $N=\infty$ problem. In the two-dimensional case we find only
cubic and quartic interaction terms, and give explicit expressions for the
vertex functions as integrals of solutions of 't Hooft equation. As examples of
possible applications of our formalism, we study 1/N corrections to meson mass
and form factors for decays of $Q\bar{q}$ states, recently discussed by
Grinstein and Mende in the large-N limit. We find that 1/N is a good small
expansion parameter.
