How to perfect pivot in ssb4?

What are the advantages of perfect pivoting in ssb4? How to perfect pivot in ssb4? I want to learn so I can improve my Marth play. Any aditional advice would be appreciated.

From the Super Smash Bros wikia page:

A Perfect Pivot is a technique in Super Smash Bros. for Nintendo 3DS and Wii U that mimics Wavedashing. It is achieved by dashing in one direction, then quickly flicking the control stick in the other direction. This will cause the character to slide along the ground in the flicked direction.

Since perfect pivoting acts like wavedashing from Melee, it can be used similarly in gameplay. Spacing and mindgames are some options, but this technique can be combined with any ground moves to be able to perform them while sliding. This opens up a wide range of options for punishing opponents or catching them off guard.

This video by My Smash Corner summarises the various aspects of perfect pivoting fairly well, including performing the technique, gameplay uses, and individual characters' slide distances.