15-20 minutes, expert
This is highly situational, so if you aren't in the purple/expert range of skill, then you may wanna skip this and work on something more fundamental.
Did you know that both your side-tilts and side-smashes can be angled up, middle, or downward by pushing your stick at a 45° angle up or down? The same can be done with your shield by holding either 2 different shield buttons or your special attack button and a shield button while angling your control stick.
This allows you to poke past your opponent's shield to land a hit. This is called a shield poke and it adds another layer to the mind games and mix-ups you can do when your opponent is low on shields.
- Spend 5 minutes with both tilt and smash attacks getting comfortable with inputting angled tilts and smashes to both the left and right.
- Spend 3 minutes on each side of the stage sprinting up, crouch canceling your movement, then inputting a down-tilted side-smash to simulate punishing someone trying to recover to the edge. After mastering it, you can practice empty-short-hops onto down-tilted (or up-tilted for platforms) smashes and tilts.
- Spend 2 minutes doing the same as above, but up-tilting towards a platform. Taller characters benefit from this and some stages have lower platforms, so still worth playing with if you're a shorty. Worse comes to worse you get stick-control practice out of it.
- Grab a practice partner and take turns (with low shields) trying to land a side-tilt on each other. How low does your shield need to be for your shield angles to matter? If you're on a platform, remember to angle your shield down, towards your opponent. If you're attacking, how low does their shield need to be for attack to poke through it? Spend 5 to 10 minutes playing out this scenario, taking turns, returning to the edge, landing on platforms, and so on.