Oh, boy! I just love the build up. Brilliant, natural progression:
In order to generate a spontaneous feeling of love and caring, first imagine an easy-to-love being (we used a helpless baby bird). Then gradually, in ever-widening circles, spread that feeling of tenderness to other imagined beings, until eventually you have imagined including all sentient beings. Finally, in a surprise twist ending, give that lovingkindness even to that person who can be the most challenging of all to love and accept: your self.
Go, find yourself a quiet corner, take 36 mins and wash your heart.