^ I'm seconding writingwithcolour. They are great!
One tip that I came across that I find super helpful is to look up "How to not write a _____ character." I've done this with a lot of my LGBT characters, but it can work for POCs, and literally any other minority group that you're not 100% familiar with.
In my experience what typically comes up is blog and forum posts written by people who belong to whatever group you filled the blank with outlining things that they see in media that they can't stand or just want to see less of. Since you specifically mentioned wanting to avoid stereotypes, I'd recommend giving it a try since that seems to come up quite a lot in these searches (in my experience at least).
Another thing that I do is just to google stereotypes for whatever group you're writing about. For me, I find it helpful if I can familiarize myself with stereotypes so that I can avoid them in my characters.