First Step: Pick a Procedure
The United States government allows immigrants to obtain permanent residency by five means:
Immigration through a family member
Immigration through employment
Immigration through investment
Immigration through the Diversity Lottery
Immigration through “The Registry” provisions of the Immigration and Nationality Act
Second Step: Apply for a Green Card
Most people obtain their green card (which signifies permanent resident status) through family or employer sponsorship, so realistically, you’ll begin your application with a petition submitted to USCIS by one of these two parties along with the appropriate documents.
If approved, the applicant must wait for a visa number to become available through the National Visa Center. When one does become available, the applicant’s last step is to apply with the Department of State at their local consulate for a immigrant visa.
Here’s a decent overview of the process.
Third Step: Wait and Pray
Processing a visa application can take years due to long waiting lists and the limited yearly admissions.