1. Plan for delays. If you are in the United States and your work permit or status needs to be renewed, realize that U.S. Citizenship and Immigration Services (USCIS, formerly called the INS) is extremely backed up. Cope by turning in your application far in advance. This is particularly important if your legal status has an expiration date on it. If you fall out of status, the immigration authorities could arrest you.
2. Consider U.S. citizenship. If you have a green card, file for U.S. citizenship as soon as legally possible. This will not only protect you from removal (deportation), but will also help you get a more secure status for your close family members. Most people have to wait five years after their green card approval before applying, but a few people can apply sooner. For more information, see the USCIS website at www.uscis.gov or the book Becoming a U.S. Citizen: A Guide to the Law, Exam & Interview, by Ilona Bray (Nolo).
3. Avoid summary removal. When arriving in the U.S. from overseas, be ready to convince the border official that you deserve your entry visa. These officials have a lot of power, and they can send you back if they think you are a security risk or that you lied in order to get the visa. Tourists should be careful not to pack anything that looks like they're planning a permanent stay, such as a résumé or a wedding dress.
4. Notify USCIS of address changes. If you're spending more than 30 days in the United States, you must notify USCIS of your changes of address, within ten days of moving. You and every member of your family must send separate notifications. You can do so either by mailing in Form AR-11 (available on the USCIS website) or, better yet, by using USCIS's online change of address service. Also, be sure to send written word of your new address to every USCIS office that's handling an application of yours -- otherwise, the office might not hear of the change.
5. File multiple visa petitions. If you plan to get a green card through a family member, see if more than one member of your family is eligible to submit the visa petition for you. For example, a brother and a sister who are U.S. citizens could both file for you, as could a U.S. citizen spouse or parent. That way, if the waiting list in one category gets especially long or if one person dies, you'll have another option in the works already.
6. Don't be late. Be extremely careful to arrive on time for any scheduled appointment with the USCIS, a U.S. embassy or consulate, or the U.S. immigration court. Arriving late -- or not at all -- can result in months of delays at best and removal from the United States (deportation) at worst.
7. Avoid visa violations. Make sure you understand the fine print surrounding your visa, work permit, or green card, and follow the rules carefully. Violating even minor terms of your visa or green card -- for example, working while you're here as a tourist or helping to smuggle a family member over the border -- can result in your visa being canceled or you being deported. For more information on the various visas and green cards available, see U.S. Immigration Made Easy, by Ilona Bray (Nolo).
8. Copy and track paperwork. USCIS is famous for losing paperwork. Send all applications and other material by certified mail, with a return receipt, and keep a copy. They're not only your proof of filing, but may become the main copies used by USCIS if the original file is never found.
9. Do your research. Be careful who you accept advice from. Rumors and friends can't be relied on -- everyone's legal situation is different. Even USCIS employees sometimes give out wrong advice, for which you pay the consequences. Do your own research where possible and, if necessary, take your unanswered questions to an immigration attorney or accredited representative whose reputation you've checked out.
10. Get help from above. If nothing else is working, contact your U.S. congressperson. They can usually make an inquiry for you, which often encourages the USCIS or consulate into taking appropriate action.
For a guide that explains how the immigration system works and covers almost every way to legally enter and live in the United States, read U.S. Immigration Made Easy, by Ilona Bray (Nolo). Or, if you realize you need help from an experienced immigration attorney, check out Nolo's Lawyer Directory to find one in your local area.