New improvements to compute Mie scattering quantities are presented. They are based on a detailed analysis of the various sources of error in Mie computations and on mathematical justifications. The algorithm developed based on these improvements proves to be reliable and efficient, without size (x = 2 nor refractive index (m = mR- imI) limitations, and the user has a choice to fix in advance the desired precision in the results. It also includes a new and efficient method to initiate the downward recurrences of Bessel functions.