Quotation marks are important. They let you know someone is speaking, and when you’re telling a story, this can be vital. I’ve seen some ‘experimental’ writing where they left out quotation marks altogether. It was confusing, to say the least.
Punctuation evolved to help writers convey meaning. After all, readers need to know where one thought stops and the next begins. They need to know how the words are being presented. Calmly? Excitedly? Quotation marks are something I find often need editing, so here are a few rules to keep in mind.
Quotation marks are for speech, not thoughts. Thoughts can be expressed in italics if you wish. Punctuation is usually included inside the punctuation marks in the United States, not outside.
“That’s the prettiest rose I’ve ever seen,” she gushed.
The first word is capitalized inside the opening quotation mark, and the comma at the end is inside the closing quotation mark. It’s a comma because there is a dialogue attribution that follows. Notice that the dialogue attribution is not its own sentence. She is not capitalized in this instance.
“That’s the prettiest rose I’ve ever seen.” She gently stroked the velvety petals.
In this variation, there is a period at the end of the dialogue inside the quotation marks. The next sentence describes the character’s actions, which serve to remind us that she is also the speaker, since it’s immediately following the dialogue in the same paragraph.