Discipline is the key. For me healthy lifestyle is a combination of your eating, sleeping, and workout habits. These things come when you follow your schedules with discipline. Also, stress relief and detoxification of your brain is VERY IMPORTANT. I would argue vacations are must for this.
In my thinking ,spending time with family, friends, and having a get together once in a month or two also makes your lifestyle healthy.

Each of us has our own motivation and innate interests to maintain a lifestyle that may or may not include some degree of healthiness. Like a continuum, establishing then maintaining a health lifestyle exists along a spectrum.

You need to find your own motivation, something that could make you feel well at any time. Typical things are quit smoking, having regular check up, get regular exercise, control what and how much you are eating and drinking. However I would like to add something that is more a thought. Are you saving the world? Probably not, so sleep well, have a positive attitude, spend time with persons you care and smile. It cost nothing, even no efforts, but these small behavior changes will make your lifestyle healthier.

Find purpose in your life. The rest is obvious and easy.

Although most people are aware of these points, still they are not able to maintain a healthy lifestyle. How can we create awareness in such cases?

“Healthy lifestyle”, awareness - these terms need to be defined in more details to focus discussion.

Let me start with relevant examples.
Smoking tabaco: dangers of inhaling tabaco smoke have been known for several generations now. It is hard to imagine that anyone who still smokes is not aware of the associated health risks, however, they make their decision to continue to “inhale”. Reasons: they like it, become addicted, see any risks as being remote, occurring sometime in a very distant future. Further, tabaco is still sold legally. Alcohol is a similar case. One way to change it would be to discontinue selling tabaco; one would expect that illegal trade would emerge but overall the consumption of tabaco might decrease as a result.

Obesity: this condition is on the increase, at least in “developed countries”. Despite information about being overweight is unhealthy, many people simply ignore it, to the point of becoming morbid. We have several choices: let individuals make their decision and be responsible for the consequent outcome, or impose limits on how much food people can eat. (It is well known that people in England were at their healthiest during the World War II as a result of food rationing.) Options are clearly available.

One could consider that free healthcare should not be available for “self-inflicted” health problems caused by smoking, overeating, illegal drug use, etc. but logistics of such an arrangement would need to be worked out in full details...