Formal:
* Dê-me: This is the most formal and polite way to say "give me."
* Por favor, dê-me: This is even more polite, adding "please" to the request.
Informal:
* Me dê: This is the most common informal way to say "give me."
* Dá-me: This is even more informal and casual, and is often used between friends and family.
Example:
* Dê-me o livro, por favor. (Give me the book, please.) - Formal
* Me dê um copo d'água. (Give me a glass of water.) - Informal
* Dá-me um abraço. (Give me a hug.) - Very informal
It's important to choose the appropriate phrase based on the context and your relationship with the person you are talking to.