We know that Shakespeare used music to help evoke the otherworldly state of the island. One example is Ariel's song. We can imagine Ferdinand, shipwrecked on the island and not knowing what is going on, hearing the lyrical notes of an invisible spirit singing of his father's (supposed) death. It creates an eerie, supernatural mood:
Full fathom five thy father lies;
Of his bones are coral made;
Those are pearls that were his eyes:
Nothing of him that doth fade,
But doth suffer a sea-change
Into something rich and strange.
Sea-nymphs hourly ring his knell . . .
Hark! now I hear them,—Ding-dong, bell.
We note, too, that lyrical, beautiful imagery depicts this death, even if delivered in an eerie way. Bones are now made "coral," and eyes become "pearls." This kind of lush imagery, even surrounding death, can reassure us that we are, broadly speaking, in the realm of comedy, not tragedy.
Another way Shakespeare creates the dreamlike mood of the enchanted island world is to explicitly mention dreams. (He uses the same technique in creating a dreamlike mood in the forest in A Midsummer Night's Dream.) For example, in a surprisingly lyrical passage to come from the mouth of Caliban, we hear:
Be not afeard. The isle is full of noises,
Sounds, and sweet airs that give delight and hurt not.
Sometimes a thousand twangling instruments
Will hum about mine ears, and sometime voices
That, if I then had waked after long sleep,
Will make me sleep again. And then, in dreaming,
The clouds methought would open and show riches
Ready to drop upon me, that when I waked
I cried to dream again.
This not only emphasizes the dreamlike qualities of the island, but offers us some concrete description of the sounds and "sweet airs"—"airs" is a pun on both the air we breathe and "airs" as in songs—so that we get a sense of what the environment is like, more enchanted than overtly frightening.
The dreamlike mood is evoked again in a famous passage at the end of the play. After learning of the actors fading into the thin air, we hear:
And, like the baseless fabric of this vision,
The cloud-capp’d towers, the gorgeous palaces,
The solemn temples, the great globe itself,
Yea, all which it inherit, shall dissolve
And, like this insubstantial pageant faded,
Leave not a rack behind. We are such stuff
As dreams are made on, and our little life
Is rounded with a sleep.