Some na-adjectives can be made polite by adding the prefix お or ご. Nouns are also made polite by adding either of the two prefixes. However, only お can be used with i-adjectives.
Note that a word that takes お will usually not take ご, and vice versa.
Are you well?
Please be happy./I wish you happiness.
Please help yourself.
Where do you live?
Are you busy?