Have all your information readily available. You will typically need your last two pay stubs and proof of residence. Residence can be proved by presenting a bill with your name and address. A utility, cable, or phone bill will work. If you do not have pay stubs then your last two months of bank statements can be used.
Be flexible. Your goal is to get a car that meets your needs and budget and start rebuilding your credit. Focus on essential things like reliability, suitability and payment. If a car meets all your needs, fits in your budget but doesn't have a sunroof, remember what's important.
Don't be rude or difficult. You have credit challenges and you need help. No one wants to help a rude person. You don't have to be a pushover to be cordial and polite.
Keep your word. To rebuild your credit you have to get in the habit of meeting your obligations. Lenders want customers who will do as they promise. If you say you will bring in a document tomorrow, do it.
Be available. Keep your appointments and answer your phone. A lender may have questions and need to speak with you. This isn't the time to hide and not return calls.