Vocabulary

Japanese	English
Hajimemashte.	How do you do?
[Name] des.	I am [Name].
Dozo yoroshiku.	Nice to meet you.
Konnichiwa.	Hello/Good day.
Ohayougozaimasu.	Good morning.
Konbanwa.	Good evening.
Sayoonara.<F>	Good bye.
Ja mata.<Inf>	See you later.
O-genki desu ka.	Are you fine?
Hai, genki des.	Yes, I am fine.
Oyasuminasai.	Good night.
Sumimasen.<F>	Execuse me.
Gomennasai.<Inf>	Excuse me.
Iie.	That's all right.
Ii tenki desu ne.	Good weather, isn't it?
Atsui desu ne.	It's hot, isn't it?
Samui desu ne.	It's cold, isn't it?
Arigatogozaimasu.<F>	Thank you.
Doo itashimashite.<F>	Your welcome.
Iie.<Inf>	Your welcome.

<F> = Formal
<Inf> = Informal

Introducing Yourself
When introducing yourself to someone for the first time start with "Hajimemashte".  Then tell them your name by saying "[Your Name] des".  Finally, tell them it's nice to meet them by saying "Dozo yoroshiku".

Thank You
Below are different forms of thank you going from less formal to more formal:

Doomo.
Arigato.
Doomo arigato.
Arigatogozaimasu.<Most commonly used form>
Doomo arigatogozaimasu.