Joker vs Pikachu

Eiha and Eigaon will not hit Pikachu easily because he's a small fast target, don't rely on them in neutral. Be wary of using bair when Pika's grounded, if it's not perfectly spaced you will miss

Use a secondary that can hit small assholes

Use safe moves grabs, and don't throw too much unsafe aerials joker tends to miss aerials against small characters

Use your down tilt, it sets up you up to use up air or back air depending when you hit Pikachu and your opponent's DI. Choose stages with platforms as it'll allow you to extend up air combos

You won't get a hit unless you use side b for long term damage