Though the atonement is what will make it possible for us to ultimately become like a god, there are key scriptures that give us formulas of how to gain this gift (the greatest of all the gifts of God). Moroni 7:45 is one of them (45 - 48). 45 has a list of attributes that are crucial for becoming like a god. Godly. Godlike. That's all eternal life is: the life like that of God. But to have eternal life, we must become the way God is. We cannot have the life of God without becoming the way a god is. My brother just moved into my neighborhood (I live with my parents in a very wealthy neighborhood who represent the 1% of the world who are in possession of most of the wealth of the world). Anyway, he moved from a small government subsidized apartment to the basement of a very expensive ($1.5 million) home (also an apartment - but much nicer). He mentioned that he was excited to live in this area mostly because he will be mingling (in the ward) with those who think differently. This is probably not the best example, but it illustrates (ever so slightly) that you have to think differently and possess different attributes to live in a different way. Mostly I want to illustrate that you cannot become like a god (AKA eternal life) if you do not think like one and act like one.
We have to become godly. If we don't truly possess the attributes of godliness but expect to just get eternal life, we are like a high-school kid who just got a C- in his general chemistry class, but wants to win a Nobel Prize for formulas on activation energy or thermodynamics. This kid will have a long way to go before he can even understand what activation energy means, let alone get a Nobel Prize. This is like us.
God is like the master chemist who has infinite "Nobel Prizes in chemistry". He has studied and researched and tested and tried and published and fought for His knowledge of chemistry. Even if we are the kid with a C- in general chemistry, we can still become that "Nobel Prize" winner. But we must understand that this endowment will only come after countless hours of "study and mastery". We basically have to become one with chemistry. We have to make the periodic table of the elements our own. Memorize it back to front and be able to recreate it if needs be. It is a part of us. We would have to publish countless papers, and present at countless chemistry conferences and write a score of academic volumes on the subject. It would be who we are. No longer a mere child, experimenting with liquid nitrogen to make ice cream - but a master chemist. We become godlike (AKA have a godlike life = eternal life) when we have become one with all things pertaining to godliness. It is possible for anyone. But they have to believe that it is possible to become a master chemist - a godlike "Nobel Laureate" - if you will.
This is the closest I can get to coming up with a comparison to being endowed with eternal life. I will include more about this in the chapter called "Eternal Living" of the book Live My Gospel. You will soon be able to find more here.