Bonjour (meaning "good day"; bon jour) hello, good morning, good afternoon.
When you enter a small traditionnal shop, like a boulangerie (baker's), boucherie (butcher's), poissonnerie (fish shop) etc. you could say "bonjour" to all the people inside.
So if there's only a lady, you would say "bonjour madame", a man "bonjour monsieur", a group of ladies "bonjour mesdames" (good day my ladies, very posh indeed!), a group of men "bonjour messieurs" (good day my sirs"), a mixte group "bonjour messieurs dames". You can also hear "messieurs dames, bonjour," or less formal "messieurs dames".
You don't have to look at anybody in particular and nobody will reply, but it is considered polite to say hello.
We say "bonjour" until it get's dark. Then we say;
Bonsoir ; good evening
Bonne nuit ; good night.
This is rather private, just for family, when you're about to sleep.
Don't say "Bonne nuit" to your French friends when they're about to leave your home!
Say "bonsoir" or "bonne fin de soirée"; have a good end of evening.
Salut ; hi/bye
Salut is just for friends, for people you say "tu" to, while "bonjour" is for everyone.
When you meet friends, you can say "salut, ca va ?" ; hi, how are you, and when about to leave, say "salut" again or "à plus", see you later, "à la prochaine" ; until next time / see you next time.
Bonne journée ; have a nice day
Bonne journée doesn't mean "have a nice trip. This is a false friend; you believe it has the same meaning as in English -journey-, while "have a nice trip is of course "bon voyage".
When you leave a small shop or friends, say "bonne journée, au revoir"; have a good day, bye (or literally, until I'll see you again).
Bon_après-midi; have a nice afternoon
Bonne soirée ; have a nice evening
Bon week end
Bonnes vacances ; have a nice holiday
Joyeux / bon_anniversaire ; happy birthday
Bonne_année ; happy new year!
à tout de suite ; see you straight away
à tout_à l'heure ; see you in a while
à cet_après-midi ; see you this afternoon
à ce soir ; see you tonight
à demain ; see you tomorrow
à ce week end
à la semaine prochaine ; see you next week
A bientôt ; see you soon (bien tôt = well soon)
à plus tard / à plus ; see you later (but you don't know when)
à means "until"
Bonne journée, au revoir, à bientôt !
source dessin ; link