IMPROVE YOUR DIALOGUE
(most fun - #5!)
1) Pick a movie to watch that you've never seen before. With the sound off, write the dialogue for a scene just from what's happening on screen. Watch the scene again with sound on to see if you picked up what was really happening. If not. Go back and match up gestures, expressions, movement, etc. to see what you missed.
2) Just listen to a scene without watching it. Listen to what is said, the rhythm, volume, pauses, interruptions.
3) Whenever you can, listen in on people in cafes, at work, on the bus, train, when someone is on the phone - especially in the bathroom! Or just women talking between stalls - you hear the craziest things. (Sorry guys, this lets you out, unless you're sharing deep, dark stuff while standing at a urinal? Are you? Do tell!). Write down what is said (you're learning how people naturally talk).
4) Write some of your key scenes ONLY in dialogue. No action or description. Just back and forth dialogue. Have characters say what they want to say without actually saying it. Each character comes from the place of want - their goal, their motivation. That should inform the dialogue. Once you have the dialogue just right. Go back to add movement, facial expression, gestures, pauses, inner monologue (thoughts/doubts), etc. where they are natural and necessary. Not just to break up dialogue.
5) Eavesdrop on children and write down what they say. Kids are brilliant. They are funny, wise, direct, curious, and unbelievably imaginative. They will teach you how to take risks in your dialogue.
Make sure to tag where needed - 'she said', 'he said'!
Extra tip: Too much talking by one character - that goes on for long periods without interruption, or too much back and forth between characters without the 'she/he said' makes for disembodied dialogue that loses impact and loses your reader.
Dialogue should always further plot, develop a character or characters, or develop relationships or conflicts between characters. Don't waste time with 'Hi, how are you?' 'How was your day?' etc. Get straight to the good stuff. Readers have enough of the boring filler-speak in their daily lives.
Watch your diction - make sure it agrees in tone and level with the character and the book itself.