If you have status and therefore earn a minimum (usu 500 miles) no matter how short the leg actually is, that can be a way to earn without flying that much more. So for example, PHL-BOS is 280 miles: my BF earned 560 miles on that trip (miles flown), but I earned 1000 (500 mile minimum). This is not counting the status bonus that you would earn on top of that.

You can use GCMap and ITA Matrix to search for distances and fares. And scan the mileage run thread here on FT.