The pencil draft doesn‘t have to be a piece of art, but the more effort you put into it, the easier the inking process will become.

Guidelines and vanishing points are excellent ways to get the perspective right.

Without them, it‘s very easy to make mistakes, no matter how experienced you are.
They may be a little bothersome to set up, but in the end you‘ll more than likely safe yourself a lot of frustration... and erasing XD .

The lower panel is a wide shot of the market place.
As you can see, I used (a rather loose) one point perspective for it.
People as well as buildings and other objects should all be aligned along these lines (or they will look like they're floating in the air or are stuck in the earth XD).