Years ago when I first wanted to learn about uC's and steppers I bought the Square 1 'easy steppin' book. One of the first circuits is a simple one where one can workout the correct sequence for any stepper, I made one and still use it today when I want to find out the stepper sequence.
Another way is to check as described above, the resistance between a coil will be twice that of the common, so with a 5 wire stepper 2 pair will be at say 150 ohms and the common will be 75 ohms. Also 5 and 6 wire unipolar steppers can be run in bipolar mode by leaving the common unconnected.
Cheers Bryan