Start with the core transaction documents: the buyer's order (the document you signed at the sales desk), the retail installment contract (the document you signed in the finance office), and any addenda or separate agreements you signed. These documents tell the story of what you agreed to and what you were charged. If you did not receive copies, you have the right to request them from the dealer.

Gather any written communications with the dealer: emails, text messages, letters, and any written quotes or price sheets. If the dealer made representations in writing about the vehicle's condition, price, or financing terms, those documents are potentially very important. Screenshot text messages and email threads and save them somewhere you can access them.

If the dispute involves the vehicle's condition, get an independent inspection. Take the vehicle to a mechanic or body shop that has no relationship with the dealer and ask them to document any defects, prior repairs, or signs of damage. A written inspection report from an independent professional is much more persuasive than your own description of the problem.

Obtain a vehicle history report (CarFax or AutoCheck) if you do not already have one. This report can reveal prior accidents, title issues, odometer discrepancies, and service history. Compare the report to what the dealer told you about the vehicle's history. Discrepancies between the report and the dealer's representations are often the foundation of a strong case.

Finally, write down a timeline of events while your memory is fresh: when you first contacted the dealer, what you were told during negotiations, what happened in the finance office, and when you first noticed the problem. Include the names of the salesperson and finance manager if you know them. A clear, organized timeline helps an attorney quickly assess the strength of your case and identify the most promising legal theories.