Being in typography and digital design courses, I have noticed a few things.
The subtext blurs into the image and is hard to read. You have used a very pretty font, and I like it. But the subheading is difficult for me to read. "Book two of (etc)" also seems to be a bit off centered.
Did your artist use a grid structure in the layout of the image? That would have helped greatly in the structure of the images and text.
I really don't want to sound like an asshole, but I really want to be honest to you, as I respect you.
Aww thanks!
I always accept heartfelt critiques! They help!
However...the imperfections are intentional.
I am proud to say that I totally did the cover myself and think it's one of my best, considering what I'm going for.
I am an antique book collector (have boxes and boxes full, going all the way back to the early 1800s!) and my goal was to make the book look imperfect, old and like it has been beat up.
I have the book in my hands now (it's GORGEOUS!) and the sub title looks absolutely beautiful and is easily legible...but the picture doesn't do it any justice.
In the story, the diary is found in a wall and so of course the font on the front of the book can't be perfect any longer, nor can the book itself.
I did what I could, considering my publisher wouldn't allow me to go too overboard.

I'm lucky she gave me any creative freedom, as I have had many publishers in the past that won't allow any creativity at all and insist on hiring a professional cover artist.
She and I had to go 'round and 'round a little until I was able to wrest some control.
But again...your critique is appreciated and if you ever do book covers for a living, you should see if a publisher will hire you.
They are always looking for good artists.