Making it means to survive or thrive depending on position in society.
means to utilize the land of opportunity that is (or was) America and leverage that your advantage in achieving set goals which you couldn’t pursue in your country of origin.
Making it varies from person to person, this concept for an immigrant might mean just to reach this land, contribute to society and enjoy the benefits of being a citizen, being able to earn and live, whereas in his/her home country there was no opportunity.
Making it might also mean amassing as much wealth as possible.
Making it may mean competing in a crowded industry and being realized as significant entity in that field, whether it may be as an artist, a company, etc.
But how do you make it?
Learn about your environment & live your in your environment.
Learning about your environment gives you an edge into what you are going into, but at the end of the day it is only secondary view of the environment.
Living in your environment gives you first hand experience as to what you have to do to achieve the goal that you have set out to do .
Allowing you to separate truth and reality from hearsay.