Buddhists hold that over 2500 years ago, Buddha provided guidance on establishing mindfulness. Right mindfulness (often termed Right meditation) involves bringing one's awareness to focus on experience within the mind at the present moment (from the past, the future, or some disconnected train of thought). By paying close attention to the present experience, practitioners begin to see both inner and outer aspects of reality as aspects of the mind. Internally, one sees that the mind is continually full of chattering with commentary or judgement. By noticing that the mind is continually making commentary, one has the ability to carefully observe those thoughts, seeing them for what they are without aversion or judgment. Those practicing mindfulness realize that "thoughts are just thoughts." One is free to release a thought ("let it go") when one realizes that the thought may not be concrete reality or absolute truth. Thus, one is free to observe life without getting caught in the commentary. Many "voices" or messages may speak to one within the "vocal" (discursive) mind. It is important to be aware that the messages one hears during "thinking" are simply discursive habit and that the real point of practice is distinguishing different types of experience from the context (mind) within which they occur.
As one more closely observes mental activity, one finds that happiness (for example) is not exclusively a quality brought about by a change in outer circumstances, but rather that realizing happiness often starts with loosening and releasing attachment to thoughts, predispositions, and "scripts"; thereby releasing "automatic" reactions toward what seem to be pleasant and unpleasant situations or feelings.
However, mindfulness does not have to be constrained to a formal meditation session. Mindfulness is an activity that can be done at any time; it does not require sitting, or focusing on the breath, but rather simply realizing what is happening in the present moment is mental content, including simply noticing the mind's usual "commentary". One can be mindful of the sensations in one's feet while walking, of the sound of the wind in the trees, or the feeling of soapy water while doing dishes. One can also be mindful of the mind's commentary: "I wish I didn't have to walk any further, I like the sound of the leaves rustling, I wish washing dishes weren't so boring and the soap weren't drying out my skin", etc. Once we identify experience as mental content, we have the freedom to cease identification with any judgments/perceptions: "washing dishes: boring" may become "The warm water is in unison with the detergent and is currently washing away the plate's grime, the sun is shining through the window and casting an ever greater shadow on the dish's white ceramics." In this example, one may see that washing does not have to be judged "boring"; washing dishes is only a process of coordinating dishes with soap and water. Any activity done mindfully is a form of meditation, and mindfulness is possible practically all the time.
For me, I'm the most mindful when I'm surfing and inspired by my surroundings. It allows me to focus on the water that I'm lucky enough to be in, the waves, and completely in the moment when riding. My goal is to make an architecture that promotes this.