I've been slowly but surely learning the spacing of her attacks and I have a decent feel for most of them. The only outliers are the dash attack and up air. Now properly baiting and punishing my opponents is an entirely different story. This is a practice that I've just now got the bare bones basics of and it takes me like three matches with someone at least to figure out their habits.
Well, when I say spacing, I don't only mean her attacks, but also the character in general. Getting a solid mastery for the character and their mobility options. JTails and a couple other guys on YT have some solid tutorials on the matter, I recommend you check them out. Smash is a fighting game focused around mobility and movement, so more than any fancy combos or whatever, you need to learn how to properly play the neutral, and in order to improve your neutral you need to feel comfortable and master all of your character's movement and defensive options so you know when it's best to do what. When do you jump, when do you SH, when do you dash, when do you WALK (yes, walk), when do you spot dodge, when do you roll, when do you dash dance, etc... etc...
I suggest hoppin into training mode, and just start practicing manual short hops + fast falls with Zelda, and then adding in attacks. You need to get very comfortable with just moving her around. Once you do, you'll start to focus less on what your own character is doing, as it'll be more natural, and more on what your opponent is doing, which is what you SHOULD be focusing on. You'll be less inclined to do things because you want to, but rather, do things in response to what you predict your opponent will do (which is the core tenet of bait and punish - getting proper reads on your opponent's actions), OR, doing things in order to force an action on your opponent, which will then let you respond with your own options.
That's the core basis of all fighting games really. At their core, they're a very complex game of rock-paper-scissors, where it kinda deviates though, is that instead of randomly throwing stuff out and hoping it works, you instead focus on reading and conditioning your opponent into doing the things you WANT them to do so you can get clean hits on them, which then leads into combos. You limit their options so they become easier to predict. It's not a game of "hit the other guy" it's a game of "get in their head so they're easier to hit." If you catch my drift.
In regard to Zelda specifically btw, there are a couple things you do wanna make sure you focus on:
-Her Farore is obviously a very good movement option both defensively and offensively, though do be careful, it has a lot of recovery frames after use, and it's unsafe on block.
-Nayru is a very good defensive tool due to the invincibility. Can get predictable though.
-Phantom is a crazy good pressure tool that can be used to througly limit the opponents options, and gives Zelda crazy good neutral
-She can do her Lightning Kicks Out of Shield, making it a very good punish options when oppents are being very aggressive.
Before you get into those though, do focus on getting very FLUID with the movement though. That should be step number 1, then the stuff up there ^^^.