There are more than 35 million legal and illegal immigrants in the United States. Staunch opponents of illegal immigration sometimes tell foreigners to "get in line" before coming to America for work. Most of the people spend years (even decades) to finally arrive in the United States. Check out the different processes to legally immigrate to the USA.
Relationship to a US Citizen
If you have a family in the United States, then you have found the easiest way to become an American. If your relative (your parent, child or spouse) is a US Citizen, then you can get a Green Card very easily as soon as your petition is approved by the USCIS (U.S. Citizenship and Immigration Services). You can become an American citizen after holding the Green Card status for 5 years (3 years in case of Spouse of US Citizen). You will just need to pass the language and civics test. The total time to become a US Citizen is 6 to 7 years in this case.
Relationship to Permanent Resident
Spouse and Children of a Lawful Permanent Resident (LPR) can immigrate to USA. However, the wait time depends on your home country. Total time to immigrate and become an American citizen is about 13 years for the spouse and minor children of a LPR.
Skilled Laborers and Professionals
If you have a college degree with some specialization either from USA or outside country, try to find a good job in the US. In this case, if you have a job offer and if your employer is willing to pay about $8000 to $10000 of legal fees to prove that you have special skills, then you can live and work in USA on a non immigrant US Visa (H1-B visa). It will take 5 to 6 years to get a Green Card and another 5 years more to get US Citizenship.
If you are a US Citizen, you can apply for your siblings' permanent residence, which will take up to 15 years of processing time.