Get good legal advice
Get screened by a lawyer as soon as possible to see if you are eligible for any legal defenses against deportation (“relief”). If you live or work in New York City, call 1-800-354-0365 between 9 am and 6 pm, Monday - Friday or call 311 and say "ActionNYC" to get a free immigration legal consult.
Be careful of scams!
Always keep your original documents.
If hiring a lawyer to represent you, always have a signed contract and make sure to review the document in your preferred language. Make sure both you and your lawyer sign the contract and you get a copy.
If hiring a private lawyer, always get a second opinion before paying and get a receipt for payment (ideally paying by check or money order instead of cash).