First of all, these are just my personal opinions. Please don't feel discouraged. And no hard feelings! Let's begin!
Firstly, I really liked your cover! But changing the font on the cover photo to a more suitable and mysterious one might be even better and effective. I suggest you take a look at the handwritten fonts, they are really good.
Another thing that I love was the fact that you made a chapter to describe the characters, and even with photos! It was really good that you made one, made the reading a lot more fun and the details crystal clear.
I loved the book but it doesn't mean there weren't cons of it. The first one I noticed that was mostly in the first two chapters was the lenght of the sentences. They were so long that I needed to stop and take a quick break, and start it all over again. You used too much (,) instead of (.), which made reading a hard time. I suggest you to shorten your sentences.
Secondly, I saw that you don't use (.) too often, nearly never. You need to use dots at the end of the conversations, sentences, and paragraphs for us, your readers, to understand everything better. Plus, using the punctuation marks in the right places will make you a better writer. Details are the key!
And lastly, I believe everything escalated too quickly. I thought Audrian hated/ feared Lumen, when did he start to have feelings towards her? Lumen had a plan, why she suddenly quitted? What secret were you talking about at the end of the 4th chapter, and why we never knew about a secret?
To sum up, I believe other than these small mistakes, your book is very good. I might even continue to read it even after the judging!
