Chogyam Trungpa on awareness and effort:

Awareness is not something that needs to be manufactured: when there is a gap, awareness enters into us. So awareness does not require a certain particular effort. Such an effort is unnecessary. Awareness is like a wind. If you open your doors and windows, it is bound to come in.
To the OP, awareness is already present in you, and like Trungpa Rinpoche says, it does not need to be a thing that you do. If you are walking down the street, just be mindful, in a relaxed, observational way. You do not need to be mindful of every pebble that you step on, or the sensation of wind on every single hair on your right and left arms as you walk. Just allow space to be aware, which in general means to unify mind and body together. If the mind and body are both focused on the same activity (and the mind is not lost in conceptualization, planning, etc.), you are, in general, aware.