This is what I've heard/learned:
Read a bunch of different kinds of material. You'll get your creativity stimulated and ideas will stir in your brain. You could also research things, or draw ideas - some other things to get your gears turning.
Every idea has been done before. You just have to put your own spin on an idea, or invert a trope to be original. There's only a certain number of colors in the world to choose from. Want to make orange, but somebody else has already created it? Just add a bit more of your yellow idea than they did, or maybe a bit of purple to make it yours (plot twist!). No big deal.
If an idea isn't working for you, set it aside and work on something else. You can let in "compost" and then it could grow into something crazy awesome with a bit of time and patience.
Personally, I say just write and have fun. If you aren't thinking about one specific type of idea, or a person you want to replicate (or a person you desperately don't want to replicate, for that matter), it's unlikely that you'll copy them.