It's fine as a motivational piece, and good on you for being so geared up that you work on other things around the project. I've always been a big fan of NaNoWriMo as a way to get people writing - though I know there are people out there who would sneer at it. It's a hell of an undertaking, so good luck.
As a cover, the imagery looks like a graphic novel cover than a novel cover, and even then it's struggling. One thing I would point out, regardless of quality, is never lay black over grey. Black will not print well from a grey background and even digitally looks painful. The typeface here is poor in the first place, but using two so wildly different weights in the same block (in this case the title) sits uncomfortably and suggests that Bunny and Girl are supposed to be separate. Advice I would give anyone putting together their own cover is: simplify. In fact, simplify until it breaks. I'm guessing this is some manner of hardboiled murder mystery involving a magician and his assistant? Well, bunny ears and a gun would convey that just as well. Similarly the type, many authors putting together covers think that type has to be "interesting" in the sense of quirky or representative fonts, but the idea of design is to convey the message clearly not to over-complicate it with unreadable or distracting type-work. You could use a simple system font like Calibri and it would be more interesting. Another facet of this is you don't need to put EVERYTHING that happens in the book on the cover - another something that authors doing their own do - just because your book has dinosaurs, and a scientist, and kids, and a theme park, and computers/science doesn't mean you have to put all of those on the cover, instead Chip Kidd puts half a dinosaur skeleton on the front of Jurassic Park.
As this is really a motivational piece rather than a "I want to use this cover on my self-published book" I won't really give a proper critique beyond that. Implementing a few design principles could clean this up and have it ready for real critique. But good luck for NaNoWriMo - don't fall behind!
