Applying for a US Permanent Residency card (or Green Card) is an important step for immigrants seeking to live and work in the United States.

Green Cards are issued by the U.S. Citizenship and Immigration Services (USCIS), who has set instructions and filing fees that must be followed stringently—otherwise, your application may be denied or delayed.

Below are some tips on how to avoid the most common mistakes that result in a Green Card application being delayed or denied.

1. Not making sure you are eligible for the immigration category you are applying to. Depending on your type of immigration—through a family member, employment, or investment—you must meet certain criteria before applying for a Green Card. To check whether you are eligible for a Green Card, go to www.uscis.gov/greencard

2. Relying on outdated information. Immigration forms and fees change from time to time. Although USCIS may accept older versions of certain forms, they will not accept an incomplete payment. Check current fees at www.uscis.gov (Click on ‘Immigration forms’).

3. Submitting incomplete documentation. Green Card forms require that you submit supporting documentation such as birth certificates, marriage licenses, employment verification letters, etc. The more documents you can submit to strengthen your case, the better. Always double check that all the supporting documentation is included in your packet.

4. Failing to sign your immigration forms. Many times you fill out your forms but forget to sign and date them—this may be especially true when you are filing your dependents’ forms (they must sign their own if they are not minors).

5. Filing non-English documents without translations. Every non-English document—diplomas, birth certificates—must be accompanied by an English translation—it does not need to be official.

6. Not filling out your checks correctly. Immigration fees should be made payable to Department of Homeland Security or U.S. Citizenship and Immigration Services—not the Immigration and Naturalization Service, which was the agency’s old name. Also, payments must be done with money orders or cashier’s checks—not personal checks.

7. Paying an immigration lawyer for what you can do yourself. Immigration lawyers charge you thousands of dollars for filing a stack of documents that you collect in the first place. Unless your case is very complex, you should file for a Green Card by yourself.