The only way I've ever found to make magic "more magical" due to having it occur less often is via one simple (and extremely unpopular) method:
Remove all magical combat and combat spells.
Here's the situation... most of us are going to have combats in our games. A LOT. In any 3-hour session, chances are pretty good that the DM is going to throw out at least one fight, seeing as how 3/4ths of our character sheets are full of numbers geared towards adjudicating combat.
Which means that any spellcaster will see most of the spells they cast in a day show up as a
direct result of combat-- either to attack other people, or to buff people during an attack, or to help folks recover from an attack. With this being the case,
of course magic won't feel like this esoteric, mystical, mysterious force. People are throwing around spells during fights willy-nilly! If you have several casters, any one 30-second fight is going to see more magic tossed around than probably all the rest of the magic cast outside of combat for the rest of the in-game week. And because fights happen
all the time... all these spells get thrown about
all the time.
Now... if you remove any and all spells from the game that are directly used for combat and only keep the ones for interaction and exploration, spells will obviously be used quite a bit less often. And thus with spells being used much less often (because there just aren't as many exploration and interaction spells, and they aren't all applicable in all explorations and interactions), when they do get used, it'll feel like its a fresher thing.
"Ooh! I'm going to use
Disguise Self! It's the first spell I've needed to use today!"
If that's how you as a DM and the players want to play spellcasters in your campaign, then that's great! When combats occur, all spellcasters fight with weapons because that's the only option all casters and characters have. Gandalf The White smacks people with his staff during the Siege of Minis Tirith. And the magic only show up later on after the fighting is done and the group is off walking again to be this special one-time thing for just a very specific purpose and use.
But my guess is... most players and DMs
don't want that. They want to be able to drop
Fireballs on people during fights. A huge part of the game is doing just that. But that's why magic doesn't seem "magical"... because players are dropping half their spell slots blowing crap up ALL THE TIME.
And that's also why at-will Cantrips
are not the problem here. After a wizard has thrown two
lightning bolts, rolled a
flaming sphere around the battlefield, and fired several
magic missile barrages at various targets throughout the course of a day... you're going to say that the
ray of frost he fires for two rounds is what is making things seem "less magical"? Nope, sorry. That ain't it.
If you're really looking to have a "low magic" setting at some point... count how many spells get cast in a day by your players that are directly during combat. I think you'll find that so long as that is an option for them... you're never going to have "low magic".