Dashing Your Dialogue

Part of the problem I've discovered with being a blind writer is...I can't see. Not a huge secret or devastating truth to reveal. As simple as it sounds though, it complicates what I can learn about being a good writer from reading good books. Learning to write, compress, and clarify dialogue comes from reading it as well as writing it. a few months ago I took a challenge to write a story, a complete story, using only dialogue. No tags, or movement between the words. Simply the conversation and nothing else. It was difficult, but I learned a lot
Here's a few things I didn't learn and had to have my friend Michelle Hawk show me...literally!
#1-Interrupting- When one character interrupts another character, the first line of dialogue is broken with a dash.
ex.  "I don't think-"
    "No one asked you to think.
Often writers will break a sentence off with an ellipses... This is incorrect if an interruption is happening.
#2-Movement- When movement happens in the middle of a sentence, the sentence ends followed by a quotation. A dash is inserted followed by the movement placed in between. Another dash is inserted followed by a quotation and the dialogue with a closing quotation. 
Ex.  "I'm terrified"-her hand waved casually around the room-"of this whole mess."
This only occurs if the sentence is broken up. If its two sentences broken by movement a dash isn't needed.
Ex.  "I'm terrified." Her hand waved around the room. "I'm afraid of this whole mess."
#3- Compounds- The only other place dashes are used in dialogue is to connect two or more words together.
Ex.  "He's only a 10-year-old."
     "She's my great-great-grandmother."
ect. ect. or anywhere else a dash would be employed.
It's not something you can listen to and 'hear' the difference, or at least the correct way. It must 'look' the right way in order to be grammatically correct.
Go check what ever your working on and see if you've dashed your dialogue correctly and in the meantime...Keep writing!" .