Speed based characters, from my experiences at least, more often than not attempt using their speed advantage to be overly aggressive and sacrifice their defense in turn. Against these kinds of Captain Falcons, Sheiks, Little Macs, Foxes, and Sonics, I've found it's best to to go for a calmer, more defensive playstyle, and keeping Aura Sphere charged. Since they're too busy trying to throw you off with their speed, they likely won't be expecting you to react to calmly and defensively. I once defeated a Captain Falcon like this without getting hit a single time lol =P
When they go for an attack/grab out of dashing, punish with a grab of your own, but be wary of rolling to dodge because they may anticipate this and punish with a grab/dash/smash attack. Try spot dodging out of a run or simply spot dodge in place instead. You can follow up with a couple pummels and then aerials if you throw them down or up. If their percentage is low enough, b-throw them and then fire your charged AS immediately. If they don't tech (which again, in my own personal experiences they don't normally), AS will hit them almost as soon as they hit the ground. Wavebouncing also works well, as it can trick them and they may unintentionally run into your AS charge and if they're close enough to you you can follow up with a jump-canceled u-smash or whatever it's called =P If their damage is just right this will KO them and leave them wondering "what just happened?" =P
If you anticipate them becoming careless, they won't be able to play as well because and become more predictable as they're trying too hard. If you can or feel like risking it, this is a good time to up your aggression =P
