Bonjour John, comment ça va?

Ça va bien merci et toi/vous?

Bonjour John Comment te portes-tu ?

Je me porte très bien et toi/vous?

Je me porte à merveille et toi/vous ?

In french ''toi'' is used for People around the same age as you.

''Vous'' is used for People older than you in order to show respect.

If the Person is unknown to you,you could say:

Bonjour Monsieur ( if it's a man)

Bonjour Mademoiselle (If it's a lady)

Bonjour Madame (if it's a woman)

Start using them right now.