hai Luis,
pa kabar?
if you dont want to sound like a stranger, here is some tips for you
Change the word 'saya' to 'aku/gue', 'memang' to 'emang', 'sudah' to 'udah/dah', 'selamat' to 'met', 'tidak' to 'ga', 'semoga' to 'moga', 'saja' to 'aja', and almost (but not all) the words end with '-kan' can be changed to '-in'. ex: 'menemukan' >> 'nemuin'
ok, i hope it works ^^