I am second guessing myself over when to capitalize "south" and "southern"...

Usage seems to vary, but I *think" the rule is:

Capitalize when part of a proper noun, a recognized region or place name (the South, South Louisiana, the South Side of Chicago).

Don't capitalize when it's simply descriptive or directional (south of 23rd Street, the south end of town, southern exposure).

Sometimes it's hard to know what's a recognized region. I think Southern California is, Southern Ohio might be, southern Rhode Island probably isn't.

But "Southern" is what's really giving me problems, especially when it refers to the culture of the American South.

Do you say Southern writers, Southern music, a Southern accent?