How to infer the meaning of life
All humans deserve to live their lives fully. But the facts are quite different. Even a single individual rarely enjoys all stages of life in a satisfying order.
Among us, some are rich, some are powerful, some are high achievers, and others live a non-fulfilling status and are always below the mark. 
Social norms and beliefs, resources and lack of resources, opportunities or absence of privilege make it difficult to infer the purpose of our existence on this globe. 
Most of us fail to estimate our inbuilt system, which is our "unexplored" ability to make our lives meaningful. This is the greatest gift of nature to the human race. 
Normally, we pay maximum attention to our social conditioning, background, ranking in possessions, and power as the criteria to decide where we stand. It is a gross misnomer. 
An individual with a weak background has been found to be doing exceedingly well. What is this? The common strategies are to make use of innate strength and to be immune to external conditioning.
We have been given a variety of strengths like intelligence, persistence, tolerance, and acceptance, as well as many weaknesses like laziness, greediness, and hatefulness. Increasing our strengths and decreasing our deficiencies play a decisive role in making us great in any domain. 
After traveling a long distance, people find out what they have done for their own necessities and what they have contributed to the whole landscape. In such conditions, the meaning of life is derived to some extent. There are people whose worthiness came to the attention of the masses after they left.
There are people who have never tried to move beyond their survival, and they have never bothered to inquire what the meaning of this precious life is.
Progress is the law of nature. We all are here to care and share and to make this world better than what we got. We are all capable of doing it to varying degrees. 
Let us check what we have done so far.