An illusion manipulates the senses. Through creating illusions, a person can attempt to manipulate another person's perceptions of the world around them by seemingly altering elements of reality.
A deception manipulates facts or truths, or what a person believes to be facts or truths. Through deceptions, a person attempts to manipulate another person's beliefs and change their behavior.
There are many deceptions throughout Shakespeare's The Tempest, but there are only two illusions in the play: the tempest and the banquet.
In the first scene of the play, Prospero conjures up a storm. He manipulates the wind and the sea to create a false perception for the passengers and crew on the ship, who think they've been shipwrecked by the elements. In reality, this was all orchestrated by Prospero's magic.
In act 3, scene 3, Prospero presents Alonso, Sebastian, Antonio, and Gonzalo with the illusion of a sumptuous banquet. As they approach the food-laden table, Ariel claps his false wings on the table, and, "with a quaint device, the banquet vanishes" (stage directions after 3.3.65).
The "quaint device" is a stage trick, an illusion. The simplest way to do this is to have a "flip-top" table that can quickly rotate from a food-laden tabletop to an empty tabletop when Ariel hides it momentarily with his false wings. Alonso, Sebastian, and Antonio hungrily reach for food that suddenly disappears before their eyes.
In act 4, scene 1, Prospero causes a masque to be enacted for Ferdinand and Miranda, in which Ariel and his "meaner fellows" portray the Greek and Roman goddesses Iris, Ceres, and Juno. This is neither an illusion or a deception. It's simply a "play-within-a-play" that Prospero promised to Miranda and Ferdinand as an example of his magic, what Prospero calls "some vanity of mine art" (4.1.44).