Ooh, I like this one. Based on the cover I would guess this is a book about an angel, due to the gates. I don't know if that's what you're trying to get across, but I figured I'd let you know that that's what I thought of. Pearly gates, ghostly sort of figure...so if that's what the book is about, I think you did a good job letting us know - between the pictures and the title - without telling us in your description.
So I know first hand that designing book covers can be a bit tedious. I've tried and failed a few times myself. But there's always a few tips I like to try and remember and base my cover around. 1.) Base it as closely as you can to the story.
Especially if it's a cover for someone else, you want to make sure it's as close to something they would like as possible.
2.) Include some type of eye-catching quality that'd make you want to pick this book off the shelf of a bookstore if you saw it.
The novel could be the most exciting thing in the world, but if the cover doesn't do the story as much justice as the content of what's inside, it may just get overlooked. As much as a stereotype as it may be, some people do tend to be drawn in by an interesting cover. Go for unique, never too simple. The cover art you have here seems a bit too plain than I might've liked to've seen. The concept seems right, but it just doesn't seem to quite pop.
3.) Be careful with which fonts you choose!
Yes, fonts can be just as crucial a choice as the cover art itself. You want some form of continuity going on. You don't want too much of an overly decorative font and have a much simpler cover. There's too much of a gap separating the two and it seems to come off looking a bit too un-matching. I see you've sort of done something like that here. Another thing, you don't want the title font to necessarily be the same exact font as your secondary font. There needs to be a distinct contrast in size as well. What I would do to fix this is tone down your title font so that it's something a bit more muted to match with the cover art. From there, choose an even more muted font as your secondary font. But be sure there is always some continuity present!
Anyway, don't be discouraged in any way by my suggestions! I think that you could have a really awesome cover if you pay attention to the details I've mentioned. I wish you luck with future cover designing, and hope anything I might have mentioned may be of great use to you.