Probably most successful songwriters have an innate songwriting ability.
No matter what you do, you'll never run away from you.
One other thing, if it's possible, as songwriters, you should also develop yourself as record producers.
I know at the beginning of our careers, my wife and I were gut wrenchingly competitive.
It's very hard to teach someone how to write a song if to begin with there's no creative crop to harvest.
It's amazing how a competitive nature can turn a negative into something positive.