In the twelfth discourse of the Bhagavad Gita, Krishna explains to Arjuna that the path of devotion is easier than the path of knowledge. The path of knowledge requires one to give up his or her attachment to the body and to have dispassion for all things in the world.
To practice devotion, one must centre the mind on the Lord and each time thoughts waver to something else you bring them back. If that proves too difficult, then one must simply devote all actions to the Lord. One who surrenders to the Lord and abandons the desire for particular outcomes attains the peace they are seeking.
Krishna goes on to outline the qualities of a devotee: they are not attached to anything and have no aversions either; they have equanimity of mind in all circumstances; they have no desire for anything; they see equality everywhere; they are untouched by sorrow, fear, honour and dishonour; they are content, always, with what is.
Deepak Chopra describes in one of his books the difference between happiness and bliss. He says that happiness is always for a reason external to us. Bliss, however, is internal. Bliss in an unshakeable state of being that exists at our core. I interpret this discourse to be akin to that. As humans we go through our ups and downs. It’s part of life and we learn to appreciate the contrast between pleasure and pain, light and darkness. When we are able to embrace both sides of the experience and remain blissful within we are practicing the yoga of devotion. We are trusting that the Lord has a plan and that all will be fine.