Mind Your Own Business in Chinese / Japanese...

余計なお世話 suggests that you do not give unwanted help or advice to someone.

The Japanese characters break down this way:
余計 (yokei) too much, unnecessary, extraneous, abundance, surplus, excess, superfluity.
な (na) connecting article. お世話 (osewa) help, aid, assistance.

Note: Because this selection contains some special Japanese Hiragana characters, it should be written by a Japanese calligrapher.

不干己事不张口一问摇头三不知 literally translates as [About] matters [that] don't concern [you], do not open [your] mouth, [and] when questioned, always shake [your] head “No.”

Figuratively, this means: It is best to remain reticent about other people's affairs and to refuse to make any comment on matters that don't concern you.