The "twilight" look

Here is my first ever attempt at using photoshop! Took me ages to do this, all those layers and masks and many other options are very confusing and alien to me. The image of the model was a test shot from a studio shoot to check my settings taken on my canon 5D mki and the background is an old image I took of hogwarts at universal studios on an old Samsung i8 point and shoot then edited in Lightroom! The masking of the model could be better blended to the background but for my first effort of doing anything in photoshop I'm quite pleased. All comments and critique welcome :)