Sentence Sunday! Punctuating dialogue

I've learned over the past months that I do not punctuate dialogue correctly and I've noticed it's an easy thing for people to mix up.  So, today's lesson is on punctuating dialogue.  Aren't you excited?!

The main source of confusion is comma versus period and when to capitalize letters.

Capitalize vs Not Capitalize
"Piglet! Stop chewing on that book!" yelled Juliana.  [Here, the y on yelled is not capitalized because yelled is a continuation of the sentence 'Stop chewing on that book.' A good way to look at it is to read it as a whole sentence, Stop chewing on that book, yelled Cale.]

"Piglet! Stop chewing on that book!" The binding on the book frayed as Piglet sunk her teeth into the thick paper. [In this example, the T on The is capitalized because a new sentence is beginning.  'Stop chewing on that book' is separate from 'The binding on the book...']

The book frayed as Piglet sunk her teeth into the thick paper. "Piglet! Stop chewing on that book!" Running toward her dog, Juliana curled her fingers over the soggy, torn cover of Nevada Barr's book, Blind Descent, and realized she would have to buy a new copy. [Each of these sentences are complete on their own and so all start with a capitalized letter.]

Juliana yelled, "Stop chewing on that book!" [And here, the letter S on Stop is capitalized even though it is a continuation of the sentence 'Juliana yelled' because it is the start of dialogue.  The beginning word in dialogue is always capitalized.]

Comma vs Period

"Piglet! Stop chewing on that book," yelled Juliana. [The first time I used this example I had an exclamation point, but here I've changed it to a comma.  I would not use a period because 'yelled Juliana' is not a sentence of its own, as I said before, it's a continuation of 'Stop chewing on that book.' The comma is used to connect the tag to the dialogue.]

The book frayed as Piglet sunk her teeth into the thick paper. "Piglet! Stop chewing on that book." Running toward her dog, Juliana curled her fingers over the soggy, torn cover of Nevada Barr's, Blind Descent, and realized she would have to buy a new copy. [Just as before, all of these are new sentences and so use periods and not commas.]

"I hope," said Juliana, "That my book tasted good, Piglet." ['Said Juliana' is set off by commas because it interrupts the dialogue and is not a separate sentence of its own.]

Alright, there are a few examples and explainations for you.  If you think of any I've missed, add them in the comments section :)