If you are going to be dealing with US Citizenship and Immigration Services, obtain legal counsel or find an accredited representative to assist in the process of filing applications or petitions.
Those applying or petitioning for anything on your behalf are required to file a Form G-28 - Notice of entry of appearance as attorney or representative.
Within the borders of the US only attorneys or accredited representatives are allowed to talk to the USCIS for you and get information back.
Outside the borders of the US, a practicing lawyer or attorney in that country may act on your behalf.
If you can't afford legal representation, ask about free or low-cost immigration legal services.
Any attorney chosen must be in good standing in his or her state.
In other words, they can't be under any orders restricting their practice.
Before you pay for any legal services, know your attorney and ask to see their license to practice.
Call the State Bar Association, or check their website and verify they are indeed members.
If the attorney won't provide you with this information, find another one.
Accredited representatives must be authorized (and work for a recognized organization) to practice before the Immigration Courts, the Board of Immigration Appeals and/or USCIS.
To make sure the representative you want does have accreditation, ask to see a Board of Immigration Appeals official decision designating them as such.
If they refuse to show you this documentation, find another representative.
These representatives will either charge a token fee or none at all.
Notary publics, notarios and immigration consultants are not able to represent you, and they must not give legal advice of any sort.
They are not considered to be qualified in legal or immigration and naturalization matters.
They may only charge a small fee for helping to fill out USCIS forms.
Notarios in the United States are not attorneys.
Beware of whom you pay for advice on immigration issues.