We propose a velocity-free attitude stabilization scheme in which neither the angular velocity nor the instantaneous measurements of the attitude are used in the feedback, only body vector measurements are needed. To overcome the lack of angular velocity, a first order linear auxiliary system based directly on these vector measurements is introduced. Almost global asymptotic stability results are obtained. Also, in order to adjust properly the gains of the controller, an analysis of their effect on the closed-loop dynamics was performed. The effectiveness and performance of the proposed solution are illustrated via simulation results where some comparison with existing previous work are given.