One of the canonical rules of pizza delivery, this rule is easily stated: When making multiple stops in different parts of the city, try to minimize the number of left turns taken. It's a simple idea, and one that all drivers probably follow to some degree in everyday driving. In any field (food or otherwise) of delivery, where each unnecessary minute or mile costs you part of your salary, it becomes much more important. Turns across traffic waste time, as do forced merges into the left lane, and long waits at left-arrow style stop lights. By optimizing your route against left turns -- or right turns, in countries that drive on the left, -- you avoid all of these.

Of course, depending on how the city is designed, not all points may be accessible by taking only right turns. Real-world issues such as one-way streets and low speed limit residential areas can influence the route chosen. Still, keeping as close to the dogma of "All Right Turns" will do your delivery times quite some good.

Of course, this only holds in countries that drive on the right; in countries that drive on the left the same rule stated with opposite chirality is true.