alright: lets start at the basics of the basics- greetings and goodbyes. (like any other language, there are countless of ways to say such things: so if anyone knows a few that i might not mention: feel free to just comment them right in! :3)

• konichiwa (koh-n-nee-chee-wah): goodafternoon, (sometimes used at any hour, but specifically for the afternoon)
• ohaigozaimasu (oh-hah-ee-oh-goh-zah-ee-mah-soo): good morning; also said 'ohaio' when informal
• mata ashita (mah-tah-ash*-ta): 'see you tomarrow'; somewhat informal, best if used with some one whom you're very familiar with
• ja ne (jah-neh): see you later; informal
• moshi moshi e (mo-shee-mo-shee-eh): 'hello' for answering the phone

*the i (ee) is not often pronounced

Thats only a few, but good ones to start with! gambatene!! (good luck)