1) What's the matter? - Что случилось?

2) Are you alright? - Ты в порядке?

3) What's getting you down? - Что тебя гложет?

4) What's up (with you)? - Что с тобой?

5) Why the long face? - Почему такой хмурной?

6) You look a bit down. - Ты выглядишь грустным.

7) Is there anything I can do to help? - Может, тебе чем-то помочь?

8) Do you need a shoulder to cry on? - Тебе нужна поддержка?

9) You look like you could do with a drink. - Похоже, тут не обойдется без выпивки.

10) Oh you poor thing! - Бедняга!

Привет, как жизнь? - Hi, how's life?

Как поживаешь? - the same as previous (something like - How are things?)

Здравствуй - Hello

Что нового? - What's new?

Что интересного? - Anything interesting happened in your life?

u can say -yo- but this informal greeting or howday(means how do u do ) sup ? whazzup( mean what's up) hiya (means how r u) I think that's enough :) 

как дела isn't as necessary as in other countries. In Russian it's more a real question then a greeting. I dislike hearing this phraseand I don't use it. My friends and my family know how I am, as for others - it's none if their busyness)).

I use the folllowing  

- здарОва or здарОв - for male friends.

- салам алейкум - for moslem male friends

- привет - female friends of any religion))

- здрАвствуйте - very formal

- здрАсте - less formal. Unlıke the previous one this expresses some feelings towards the person I talk to, good or bad, depending on the intonation.

- добрый день/вечер - when I'm not sure If I should say ты or вы

Как ты?- How are you?