  We present a procedure to improve the lattice definition of $\mathcal N = 4$
supersymmetric Yang--Mills theory. The lattice construction necessarily
involves U(1) flat directions, and we show how these can be lifted without
violating the exact lattice supersymmetry. The basic idea is to modify the
equations of motion of an auxiliary field, which determine the moduli space of
the system. Applied to numerical calculations, the resulting improved lattice
action leads to dramatically reduced violations of supersymmetric Ward
identities and much more rapid approach to the continuum limit.
