ur best bet is to start off learning hiragana. reveiw them a lot and make sure u know them.then do katakana,after that, do kanji. its best to learn hirgana first because u'll see a lot of it.katakana is used for foreign language.
greetings
hayou gozaimasu-good morning-used b4 10:30 or 11am
konnichiwa-hello-used after 11:30
konbanwa-good night-not used when someone is leaving at night,used after sunset
other usefuls:
sayounara-goodbye
doumo, doumo arigatou, arigatou,arigatou gozaimasu-thanks,thanks much,thank you,thank u very much
o-genki desu ka?-how are you?
o-kagesama de genki desu.-with ur honorable help i am well.(really formal)
genki desu-i am well
iie-no
hai-yes
onegaishimasu-if you please
douzo-please
yoroshiku onegaishimasu-please be kind to me if you please
abunai!-look out!be careful!
dame desu-not good
there are many more!
baibai!^_^