Now this is a piece of advice that we hear frequently. And I tell you, it used to confuse me to no end.
How could you not put the first thing first? How do you put the the third thing first? What kind of sense would that make?
However, as I have become more experienced, I have learned that you can, in fact, attempt to put the second thing before the first thing and have an ineffective, non-productive mess on your hands.