A lot of people get green cards through their own family members. If you are an immediate relative of a US citizen then you may be eligible automatically and this is a very common way to obtain citizenship in the state. You may be a spouse or you may have unmarried children that are under the age of 21. You may also be a parent of the petitioner; however they need to be 21 or over in order to fully qualify.
If you don't meet these requirements then it is possible for you to still get a green card. After all, you could be a family member of a US citizen and you may fit into a preference category. This can include unmarried sons, brothers, daughters or sisters that are over the age of 21 and those who may be related to the petitioner, but 21 years old or over.
As you can see, there are plenty of ways in which you can get a green card via your family members but there are other requirements that you need to meet as well if you want to be fully eligible for the green card. There are of course other relationships that qualify for the green card however you would need to talk to your visa advisor about this before you go ahead with your application. For example, some of them include a battered spouse or a child, a person who has been born to a foreign diplomat in the US and a widow(er) of someone who is in the United States as a citizen.
Don't delay and contact your visa advisor today to see if you qualify for a family green card and see what you need to do in order to make your application a successful one.