Conference Update #2: Writing Dialogue

I have been a huge fan of Melanie Jacobson's blog Write Stuff for probably a year or more. She is so down to earth, has great advice, and is freaking hilarious.
Anyway, the next class I'm spotlighting, was her class called Say What? Using Dialogue to Reveal Character. She started out the class with this quote:

"Dialogue's purpose, and there is no exception to this, is to create tension in the present and create suspense for what's to come." Gloria Kempton

This is true, regardless of genre.

Purpose of dialogue:

*Establish of sense of place: You could have two characters talking and have no clue where they are at. Example. If someone says, "I'm hungry." Where are they? Are they teenagers in a car who want to stop and grab a hamburger? Or are they lost on a desert island and starving to death? Adding scenery to a scene helps the reader identify more with the character. Don't overdue it and name every single thing about the scenery, but use it sparingly and let the reader know where your characters are.

*Advance the conflict in a story: Dialogue intensifies the conflict between the protagonist and the goal. Example. If someone is being held hostage and tortured for information, the dialogue will definitely intensify the scene. In other words, the dialogue must move the story forward. If you use too much dialogue, it slows the story down. If your characters don't talk about anything relevant to the story, and it doesn't do anything for the reader, then you should cut it, or have a reason they are talking about that certain thing.
I have a problem with this. I'm pretty good at writing dialogue, but sometimes I write too much. I think some things are funny that I write, but then I realize it doesn't have anything to do with the story. It slows it down and people get bored.

*Reveal elements of character: Dialogue says a TON about a character. Is he/she funny? Are they serious? Do they create conflict with everything they say to other characters?
I love this part of dialogue. It's so fun to see what your character has to say to everyone. How they interact with people. It's one of my favorite parts of writing. :)

Mechanics of Dialogue:
*Melanie also warned about "talking heads" If you have two characters talking to each other for basically a whole page and don't use dialogue tags, or beats, it gets boring. (Beats are an action the character does while talking. Example: Sally frowned. "You just don't get it do you?" So, "Sally frowned" would be a beat for that dialogue scene.
*Don't use crazy dialogue tags either. He said/she said should be used 90 percent of the time.
*Don't have your characters yell at each other all the time. Keep shouting to a minimum.
*Make sure each character has his/her own unique voice.
I think that last one is HUGE. Every character must sound different. If they all sounded the same, how boring would that be?

Anyway, I thought her class was fantastic. If you ever see her at a conference, go to her class! She is awesome! :)