Developing your character's voice is extremely hard for some authors. Here are some tips and resources I've found on this topic:
What articles and tips do you have to share?
Great links! This is so true
1. Write honestly, from the heart.
When you write from your feelings, your voice will be automatic. Of course, you’ll have to rewrite and edit, but allow your honest feelings to surface and show.
That's how I found my voice, by just writing and not focusing and all the noise, just the emotion.
Eliza, I just did some journaling a couple weeks ago and out poured this voice for a new character. By FAR the best voice I've ever been able to write!!
I write YA and I tend to use composites. Ahem, my kids are a great source. =) Eavesdropping helps too!
My 10YO is in theater with a lot of teens and I LOVE to watch their dynamics!!