To "get shet of" something means to get rid of it. (The word might have originally been "shed" but it always sounded like "shet" to me.)

"Public work" means any kind of work but farming.

"She favors her sister" means she looks like her sister; there is a family resemblance.

Threats:
I'll turn you every which way but loose.
I'll jerk a knot in your tail.
I'll take you down a notch.

Weak or ironic praise:
It's better than playing with a knife and cutting yourself.
It's better than a poke in the eye with a sharp stick.

Weather:
It's raining like a cow pissing on a flat rock.

I've heard the expression "Bless his/her heart" a lot, but I always took it as a sincere expression of pity. If you use it after a non-complimentary statement, the point would be that you did NOT intend it as an insult, but merely a statement of unfortunate fact.

Of a verbally timid person (the exact opposite of Spaw):
"He wouldn't say shit if he had a mouth full of it."

When you hear someone singing, you can ask, "What did you do with the money?" The person will probably say, "What money?" Then you say, "The money your mother gave you for singing lessons."

You can call me anything you want but late for supper.

To plague someone means to annoy them with teasing or other unwelcome attention. "She'll never get her work done with all the boys plaguing her like that."