What is a one-sentence summary of the following article?
Your ticket will have information explaining how to contest the citation and how long you have after the citation was issued. Even though you may have as many as 30 days to request a hearing or contest your ticket, do it as soon as possible.  For example, in Chicago you have only seven days to contest a parking ticket.  If there is a phone number you can call to contest the ticket listed, go ahead and call it immediately so you know you won't miss the deadline. If you can't do this immediately from your car, do what you need to do to contest the ticket as soon as you get home. Review the information the officer wrote on the ticket before it was left on your car, and make sure everything is correct and accurate. The mistake has to be a major thing. For example, if you drive a silver Honda Civic and the ticket lists a green Volkswagen Beetle, that's clearly not your car. However, if the officer wrote the ticket for a "gray Honda Civic," that's probably not enough of a difference to defeat your liability for the violation. Because ordinances in some cities prohibit officers from making a change to a parking ticket, any scribbled or scratched out information could constitute an unlawful alteration.

Summary:
Read the procedure and deadlines carefully. Contest the ticket right away if possible. Note any mistakes on the ticket. Look for changes or alterations.