- Getting involved in your local Smash Bros. community is always helpful in starting to become competitive. This not only gives you chances to fight other humans (crucial BTW, since CPUs give bad habits), but it also allows you to meet new people with similar interests.
- If you don't have much of a Smash Bros. community or friends that play, the next best thing would probably be For Glory Mode. You can pick up some bad habits and encounter some strange people on there, but all in all, you'll be fighting human beings, and this is crucial as I already pointed out, as it teaches you match-ups, forces you to make plays on the fly and relax under pressure, and allows you to eventually do some critical thinking in the Character Select screen after a loss to think about what you can change to be better. If you can, it'd probably be best to continue fighting people that give you a hard time, as these are the people who will help you gain better qualities as a Smasher that CPUs couldn't ever hope to give you.
- If you don't have a community and you don't have online (it happens, but doesn't seem to be your case), then the best thing is your Amiibo honestly. At maxed level, I'd still consider them to be better than the CPUs.