Sorry I didn't post here sooner. I was a bit distracted yesterday when you posted this.
Zelda, as a character, is designed to be a defensive character. With her new phantom, I suspect Sakurai wanted her to be using this to wall out her opponents and pepper them with Din's fire. While phantom is a useful spacing tool as long as it's not charged to level 3 (after the patch that gave it a hitbox on travel), Din's isn't which makes her camping game really awkward since she doesn't actually put on the ranged pressure necessary to be a true camper. That said, she also lacks safe approach options, so where does that leave her? The best description I've heard of Zelda's play style is that of a hybrid turtle/aggro character.
Basically, Zelda will be her most effective when she's keeping her opponent at a distance from her around the max range of fsmash, ftilt, dtilt, utilt, and jab. Nair is also a great spacing tool once you figure out its disjoint. Around where phantom 1 would hit with the middle of its sword. If the opponent approaches Zelda, she can use all of those tools to stuff their approach (Jab in particular and dtilt for combo setups where fsmash and ftilt are more for outranging an opponent's attack or as punishes). Once Zelda gets the opponent in a disadvantageous position, she can push her advantaged state for a little while by giving chase with some of her true combos like jab to Dash Attack, dtilt to nearly any aerial, and she can also look to bait an opponent's airdodge which Zelda takes advantage of really well with Lkicks and elevators. Unfortunately, Zelda can't push her advantage as long as other characters like Sheik or Mario can since she doesn't have amazing frame traps or long true combos etc which means she has to return to a turtle playstyle when the opponent is able to reset to neutral because her neutral game leaves a lot to be desired.
As Dionysus said, a Zelda player should be using every mindgame and mixup possible in order to fake out the opponent. Because of her lack of options in the neutral game, the Zelda player has to get inside of their opponent's heads more than most other characters that can just press the A button for a free win (I'm looking at you Mario mains). Take advantage of empty hops into grabs, short hop airdodge into Nayru's Love or bair or nair, airdodge or dair while falling and Nayru's just as you're about to land so the opponent will get punished for thinking you're punishable and, eventually, ledge cancel FW to dair or nair for tricky kills. Use Zelda's shifting hurtbox during her attack animations to microspace against your opponent. Fsmash's hurtbox shift is especially dramatic (I've gotten caught in a Falco rapid jab, fallen out, input fsmash and charged it until the combo finisher came out which doesn't hit Zelda while she's charging fsmash and gotten a huge punish by releasing it). A Zelda player should have an accurate sense of the range on all of her tools so the player can outspace opponents with her disjoints.
And remember, if you're facing people that are unsafely spacing against your shield, they should be regretting it. Zelda has some of the best tools OoS in the game with Nayru's Love, bair, and FW.