Swabhava is the Divine Impulsion in everything. Its unmistakable sign is that it comes naturally to you, without any external consideration or outer compulsion or social conditioning. To identify it one has to quieten the mind and the vital desires / ambitions and see what arises spontaneously within you as a sure inspiration of the thing to be done. Once you identify with it then there follows a great natural joy and satisfaction, at the very effort in the direction indicated by the swabhava regardless of the result.
Affectionately,
Alok Da