So here are a few tips that may get you thinking or your characters talking:
1) Dialogue is not like speaking in real life
Take an afternoon and visit your local coffee shop. Order your favourite drink and have a seat. Eavesdrop on the conversations around you. You'll get a sense soon enough that normal conversations are not like dialogue in a novel. There are ums and ahs, and for the most part, it's rather boring.
Dialogue is never a faithful rendering of how people truly speak. It's shaped and concentrated. When you're writing dialogue always keep these two questions in mind: i) What is it doing to reveal character? and ii) What is it doing to move the story forward?
2) Make sure your characters speak to the times
This is particularly important if you're writing a historical novel. Your characters need to speak the way your readers perceive characters to speak during that time period. However, be weary of being too verbose or you may lose your reader's interest fast.
3) Too much, too little
There are ebbs and flows to conversations. If you notice that a particular character's dialogue has taken up half a page (and it's not a soliloquy), review the passage and ask yourself how you can break it up to make it more interactive.
If the conversation looks like sixteen one line sentences (back and forth between two characters), see how you can slow it down. What are the characters thinking as they speak? How are they acting? This will help make the dialogue feel rich and full to the reader.
4) Don't worry about slang
This is particularly true in writing for YA. Sometimes we focus too much on trying to emulate how kids talk these days. But by doing this, we may actually be dating our writing or risk alienating kids. Using words that some kids in one region use may not resonate with other kids in different communities. It's important to be authentic to the story but that doesn't mean we need to use the latest teen buzzword to make things seem real.
Do you have tips or experiences writing dialogue? Feel free to share them here!