* Rêver de: This is the most common and general way to say "dream of".
* Example: "Je rêve de voyager en Italie." (I dream of traveling to Italy.)
* Faire un rêve de: This is used when talking about a specific dream you had.
* Example: "J'ai fait un rêve de toi hier soir." (I had a dream about you last night.)
* Avoir envie de: This means "to want to" or "to have a desire for", and it can also be used to express a strong desire or dream.
* Example: "J'ai envie de devenir écrivain." (I want to become a writer.)
The best way to choose the right phrase is to consider the context of your sentence and the level of formality.