"Enhances the effect of your next step" means you will inflict the enemy with 2 levels of daze with a single step whilst under the effect of Presto.
Successfully hitting a step whilst under the effect of Presto will grant one additional finishing move.
If the enemy is already afflicted by a level 10 daze effect, only one finishing move will be granted for successfully hitting a step, regardless of whether Presto is activated or not.
Grants a currently unknown, fairly large amount of accuracy to the next step.