  The simultaneous treatment of static and dynamical correlations in
strongly-correlated electron systems is a critical challenge. In particular,
finding a universal scheme for identifying a single-particle orbital basis that
minimizes the representational complexity of the many-body wavefunction is a
formidable and longstanding problem. As a substantial contribution towards its
solution, we show that the total orbital correlation actually reveals and
quantifies the intrinsic complexity of the wavefunction,once it is minimized
via orbital rotations. To demonstrate the power of this concept in practice, an
iterative scheme is proposed to optimize the orbitals by minimizing the total
orbital correlation calculated by the tailored coupled cluster singles and
doubles (TCCSD) ansatz. The optimized orbitals enable the limited TCCSD ansatz
to capture more non-trivial information of the many-body wavefunction,
indicated by the improved wavefunction and energy. An initial application of
this scheme shows great improvement of TCCSD in predicting the singlet ground
state potential energy curves of the strongly correlated C$_{\rm 2}$ and
Cr$_{\rm 2}$ molecule.
