To sound more natural try using these in informal situations. 
Yo
Hiya
Whatsup?
Howdy
Hey hey

Follow me for more Everyday English.

Everyday English with Teacher Alyse

How to Say Hello Like a Native Speaker?

Οι μήνες του χρόνου!

Ιανουάριος
Φεβρουάριος
Μάρτιος
Απρίλιος
Μάιος
Ιούνιος
Ιούλιος
Αύγουστος
Σεπτέμβριος
Οκτώβριος
Νοέμβριος
Δεκέμβριος

My Lovely Greece

Months of the Year in Greek -  Vocabulary 2

Listen and Repeat the days of the week in Greek:
Δευτέρα for Monday
Τρίτη for Tuesday
Τετάρτη for Wednesday
Πέμπτη for Thursday
Παρασκευή for Friday
Σάββατο for Saturday
Κυριακή for Sunday

Days of the Week in Greek - Vocabulary 1

Μια μέρα στη Θεσσαλονίκη - Να γνωρίσουμε την πόλη και τι μπορούμε να δούμε!

Welcome to 'My Lovely Greece' - Easy Greek stories. This podcast is made for students learning Greek for intermediate level. First you can hear the narrated story at a slow pace, after you will hear again the same story at normal native speaker pace.

Happy listening!