Sorry bro can't say much good things about this one.
First off you're colors are quite rich and very inviting but then you clash them with a black and white effect. On top of that you're render is also black and white. The style now tends to stray from black and white work with the occasional exception. This style of B&W with a splash of color works quite well for advertising and drawing attention to where you want it but not so well in a personal piece.
Another thing I'd like to point out is the lightning. Something happened there that I am not quite sure of. The Lighting (stock?) gets cut off on the clouds and there are plenty of other small parts that were poorly erased. Not sure what happened, maybe lack of time or effort? You're lighting isn't too bad though but it could be better.
Another thing I'd like to point out to you is your placement. If you are unaware of the rule of thirds I would advise you to look it up on google, I'm sure you will find plenty of information on it there. Basically you don't want a focal point of your piece to be centered or way off center. Assuming you know what it is, I will just tell you that your text should be moved and your render should be moved slightly closer to the center. Also because of the way the castle in the background is portrayed it is a little eye catching and may also want to be moved off center but seeing as how that shouldn't catch ones eye you may want to fix that in other ways.
Besides all that it's not bad, good idea just needs a little fixing up.