Perforated tart frames.
Some people freeze their dough and make perfect strips etc with a ruler. You should also have a perforated silpat and a baking tray to let air go through. Some have pro equipment to make the dough perfect when rolled out.
That's the short story I guess, and technique. Years of practice I guess? And maybe some Photoshop?
You can do pretty good with the right tools, this is my first ever attempt on a tart shell;