For legato, keep absolutely even pressure. Like toothpaste being squeezed out of a tube. Scales should sound as if they are superimposed on one long tone. No yanks, checks, or wobbles. Push across fingers.
Emphasis is prepared by the breath, carried out by the tongue.
It is never made by a finger accent. No spaces between notes. Some players have been taught that music stops where staccato begins. Rather, music stops where legato stops, and legato stops where bad staccato begins. Good staccato is a judicious combination.