Powershield, WD back OOS, retreat fair OOS, dash attack.
Try to learn the spots in Falco shield pressure where he is vulnerable. Shield grabbing (or up B OOS at high %) is good if you know it will work (like recognize when he has done an aerial too early).
Rolling out of pressure is also really good if it's not getting called out cause shine grab is really OP.
It's imperative that you get good at dealing with knocked down characters when fighting Falco. Space around get-up attack, don't fall for regular stand up -> shine. The worst is when you finally hit the bird and then he just starts a combo out of your failed tech chase. Falco preys on the anxiety that comes with feeling like you NEED to convert every time you get an opportunity.