These tips apply to all my gingerbread houses:
After I decide on which house to create, I make a template out of card stock paper. From that, I make patterns from freezer paper.
The freezer paper doesn’t stick to the dough when I’m cutting the pattern. The dough was made up 3 hours prior and kept cold in the refrigerator. I use a pizza cutter and a straight edge to cut out the pieces.
Sometimes the dough forms bubbles while baking. As soon as you take the pieces out of the oven, you should use the rolling pin to even out the dough and roll over the bubbles.
After the cookie pieces have cooled, I use a file to even out the edges. You can see the difference in the photo below. The first piece has been filed and the piece on the right is out of the oven. They will line up better when I’m ready to assemble – all the edges will fit together after they’ve been filed.