Crescent, you're the first person I've heard of who's picking up a pocket zelda for a specific match up, but it's true that against spacies who are inexperienced against zelda, she can do very well.
Techniques:
1) Master land-canceling nayru's love as this will be essential for dealing with his lasers and approaching him. After you've learned the timing for that, practice mixing up what actions you land-cancel into so that the falco doesn't always expect an attack and just try to shield grab. You can make any action after the land-cancel so mix up attacks, grabs, dashing away and then coming back to punish, or even another nayru on the ground. Keeping your opponent scared of your length and disjointed hitboxes is the key to pressuring with zelda because she's slow. Land-cancel nayru as a counterattack is probably your best option for a grab.
2) FWAD (farore's wind air-dodge) doesn't need to be mastered from every possible angle, but you should be able to do it on command to close larger distances to maintain pressure. Falco's lasers make FWAD a little less useful in the MU since anytime they hit during the 33 frames it takes for her to disappear, it will cancel your teleport. Use FWAD more when you've hit him and you need to close the distance for a followup. If he's stupid and not using his lasers to punish your FWAD's then it would still probably be more advantageous to through out a din's mine
3) Learn to DI well and consistently. Being floaty doesn't mean you're immune to combo's, you still have to work consistently to avoid. Nayru can be helpful to break some combo's, but not all, and it doesn't protect you from vertical combos, which falco excells at.
4) Practice the spacing/timing of bair, fair, utilt, ftilt, and to a lesser extent, uair, jab, and dtilt. Nair, nayru, and usmash are easy to grasp.
5) don't get distracted with din's fire, since you won't be able to capitalize on them until you've mastered zelda's core hard hitters (bair, fair, utilt, nair[not a heavy punisher but easier to use and good for damage]). If you can get one out safely, go for it, but don't expect much until you've learned to anticpate where they're gonna be and where they'll go if they get hit by a dins fire mine.
6)Control the situation. This is good for all characters, but especially for zelda because it's how one deals with her glaring weaknesses, which are that she lacks mobility and has awful endlag on her moves. Get good at predicting>punishing and goading the opponent into doing something you can punish. This is the most important step to understand, but I've placed it last because you must first master the above steps before you can control your opponent successfully.
Hope that helps!