Exploring a new town

Let me start off by saying that this piece did catch my attention well. You have a pleasantly soft colouring style, and the contrasts of light and dark in your shading are effective. The soft colours make for a very unified-looking piece.
However, I do have to say that several errors were some of the first things I noticed as well. Most notably, Luke's right eye is touching the side of his head. While this series' art style doesn't exactly lend itself to anatomy, this error means that Luke's stare is rather blank, and he appears rather walleyed. It is very distracting to me. Next time, try moving the eye closer to the nose, when drawing in a three-quarter view such as this.
Next, perspective. I do like what you were going for here - exaggerated, rather epic perspective to show a backround as well as an interesting angle from which to view the characters. However, the fact that Layton is seen from a bird's eye view and the town is not is jarring, and makes Layton appear out of place. While I understand how this has made your composition more effective, it is still distracting. Foreshortening is definitely difficult, but next time, maybe try and place the backround on the same "level" as the characters - meaning that the town would be seen with the rooftops most visible.
Finally, your light source. This is a more minor problem than the rest, because the possibility of other buildings and the way Luke and Layton are standing give them some leeway from this. However, it seems as though the sun is facing from two different directions. From left, it is lighting up the town and the Professor. From right, Luke's face is being shone on directly. He should be darker overall, as he is behind a wall.
Overall, this is an appreciable piece, and I see where you have put in a lot of effort. I hope you take my suggestions into consideration for the future.