Again, mounting from both sides equally allows horses to use the muscles on both sides of their spine in a more uniform fashion, simply being better for their backs.
Always hold your reins in your left hand, on contact, as you mount, so that you have control of your horse, and place your left foot into the stirrup. Push your weight up and over your horse, carefully swinging your right leg over his back without brushing or kicking him. Ease down into the saddle gently so you don’t hurt your horse’s back, sit tall, and push your heels down as far as you can towards the ground, while keeping the pressure of the ball of your foot pressed down into the stirrup.