I can’t create believable characters – they seem to lack their own voice.
Here’s a practical exercise that can help you get started:
Picture the last time you felt a strong emotion. Now write for 15 minutes about that experience. Don’t correct your writing. Don’t criticize yourself. Don’t change words to make yourself sound smart, cute or insightful.
Now read your work. Chances are, there is feeling in what you’ve written…
If you can replicate this experience, while putting yourself in the shoes of a character, your writing will develop into a more authentic and realistic piece.