Hell-ou :)
from the top of my head I'll try to answer you with something. The words for I, me: watakushi (kinda formal), watashi (neutral), boku (slightly more masculin but females use it too), ore (masculin. Maybe kinda macho as well), atashi (humble). I'm not completely sure how the nuances of these pronouns sound in real conversation with a native (f.ex., if you're talking with a Japanese person and continually refer to yourself using "ore", it might sound a bit cocky, haha). Aaaaaaand... I guess you probably know that in Japanese the personal pronoun is often omitted from the sentence if it is obvious that you're talking about yourself.
I have/ I don't have -> which verb to use, aru (non-living things) or iru (living things) when saying f.ex. that you don't have something.
X ga aru -> there is X, X exists (something not alive, a thing)
X ga iru -> neko ga iru (something alive, living) (there is a cat/ a cat exists)
present tense: plain - polite in 'there is, there isn't' conjugations:
aru - arimasu, nai - arimasen
iru - imasu, inai - imasen
I dunno, is this helpful at all? :/