* Γειά σου (Ya sou): This is the most common and informal greeting, used among friends and family. It's pronounced "ya-soo".
* Καλημέρα (Kalimera): This means "good morning" and is used until noon. It's pronounced "ka-lee-me-ra".
* Καλησπέρα (Kalispera): This means "good evening" and is used from noon until late evening. It's pronounced "ka-lee-spe-ra".
* Καληνύχτα (Kalinichta): This means "good night" and is used after late evening. It's pronounced "ka-lee-nee-hta".
You can also use γεια σας (ya sas), which is a more formal greeting, similar to "hello" in English. It's pronounced "ya-sas".
Remember that Greeks are very friendly and welcoming, so don't be afraid to try using these greetings!