Computing the basic accretion parameters for the supermassive black holes expected to be present in quasars is still a major challenge. In this paper we stress how a systematization of observational properties through the so‐called “eigenvector 1” of quasars helps to develop a clearer view of the structure and dynamics of the Broad Line Region. “Eigenvector 1”‐based results also provide guidelines for more reliable estimates of the black hole mass and Eddington ratio over a wide redshift range, 0 ≲ z ≲ 2.5. We summarize the results of computations for a sample of ≈ 300 low and intermediate redshift quasars, and we suggest that black hole masses may not generally exceed ≈ 5 ⋅ 109 M⊙. We also found no convincing evidence of sources radiating above the Eddington limit.