  We present a combined computational and experimental study to optimize the
efficiency of evaporative cooling for atoms in optical dipole traps. By
employing a kinetic model of evaporation, we provide a strategy for determining
the optimal relation between atom temperature, trap depth, and average trap
frequency during evaporation given experimental initial conditions. We then
experimentally implement a highly efficient evaporation process in an optical
dipole trap, showing excellent agreement between the theory and experiment.
This method has allowed the creation of pure Bose-Einstein condensates of
$^{87}$Rb with 2$\times 10^4$ atoms starting from only $5\times 10^5$ atoms
initially loaded in the optical dipole trap, achieving an evaporation
efficiency, $\gamma_{eff}$, of 4.0 during evaporation.
