Hi there. First off, welcome. I think it's great you are using contests to try out new writing skills. I've used them myself over the trees for different skills and genres. Great way to work on writing.

As for finding a mentor, a little more information might help. Is there a specific genre you write or plan to write? Is there a word count length you are going for (short story, novella, novel for example)? Would help to know as we all have different focuses and experiences. Like I tend to write speculative fiction, romance and young adult but am not of much help with horror or mysteries.

Good luck to you and hopefully you can find what you're looking for on the site. Have fun writing.