In order to become aware of your passion, you must take action. Taking action is key! Opening a door is an action. You have to put your hand on the knob, turn it and pull. Some doors have to be pushed open. In any case, some action must be taken to get to the other side. Becoming aware of your passion is all about taking action doing things you love to do.
Another thing you must do is to acknowledge that your passion already exists. It's interesting that for those who say they don't know what their passion is, they do have an idea about what it is not. What do you love to do? What would you rather be doing with your time? What brings you joy? Answering questions like these will help you to become aware of your passion. Also, keep in mind that we are creative. We create with our words, thoughts and actions. It will be helpful to change your language about "finding your passion". Start by acknowledging that you do know what your passion is, because you really do! Create an affirmation or declaration to repeat. For example, "I am becoming more aware of my passion everyday." Realize that saying you have not "found" your passion is saying that it is somewhere outside of you. Please look within!
"Don't ask yourself what the world needs; ask yourself what makes you come alive. And then go and do that. Because what the world needs is people who have come alive." -- Harold Whitman
"Without passion man is a mere latent force and possibility, like the flint which awaits the shock of the iron before it can give forth its spark." -- Amiel
"The more intensely we feel about an idea or a goal, the more assuredly the idea, buried deep in our subconscious, will direct us along the path to its fulfillment." -- Earl Nightingale