Write what you don't know but are interested in knowing.
Sick of writing what you know? Time to write about what you don't know but are interested in getting to know.
When I'm interested in something I'm determined to find out everything I can about it. I read from books and on-line, I talk to people, I try it out, I journal about the experience. I'm so passionate about the new love in my life that I can't stop thinking about it!
This enthusiasm for a new topic will come across in whatever you write about it, whether it's a how-to article, personal story or profile of an expert. Being new to the topic, you will ask questions that those more familiar with it may not. You will look at the topic from different angles than someone who's more experienced might.
Think of something you've always wanted to try or explore in more depth. Give it a whirl and write about it. It won't just open you up to a new world of experiences but open up your writing world too.