People
The person words every conversation needs: I, the name suffix, everyone and oneself.
watashi
I, me (neutral)
私 わたし
The neutral 'I', safe for anyone in polite speech, though men usually switch to boku or ore casually; it is dropped whenever context makes it clear and used mainly for contrast or 'me too'.
watashi mo iku.
I'm going too.
私も行く。
watashi mo ikimasu.
I'm going too.
私も行きます。
Saying watashi in every sentence sounds foreign; drop it unless you're contrasting. In casual speech men usually say boku or ore and women watashi or atashi; with desu/masu, watashi suits everyone.
-san
Mr./Ms. (name suffix)
〜さん さん
Attaches to a name, a job or a shop (tanaka-san, omawari-san, panya-san) as the default respectful suffix, but never on your own name, or on your own family when talking to outsiders.
tanaka-san mou kiteru?
Is Tanaka-san here yet?
田中さんもう来てる？
tanaka-san wa mou kitemasu ka?
Is Tanaka-san here yet?
田中さんはもう来てますか？
Where English says 'you', use the person's name + san (tanaka-san wa dou?); anata sounds distant or presumptuous. -kun (boys, juniors) and -chan (children, close friends) are the casual alternatives.
minna
polite minasaneveryone; all of you
みんな 皆さん
Everyone in the group (minna de = all together); in polite speech minasan addresses or refers to other people.
minna genki ni shiteru?
Is everyone doing well?
みんな元気にしてる？
minasan ogenki desu ka?
Is everyone doing well?
皆さんお元気ですか？
Keep minna when you include yourself (minna de ikimashou); minasan is for others.
jibun
oneself; myself
自分 じぶん
A reflexive 'self' for any person: jibun de (by yourself, on your own) and jibun no (your own).
jibun de yaru yo.
I'll do it myself.
自分でやるよ。
jibun de yarimasu.
I'll do it myself.
自分でやります。
In Kansai, jibun can also mean 'you'.
Learn first: watashi