Roberta,
You can contact or visit your local dealership, they should provide you with a free brochure or information on what is recommended by the manufacturer for the particular intervals such as 30k, 60k, 90k, and so on pertaining to your specific year of vehicle. It may consist of a coolant flush, transmission flush, brake check, tire balance, and a few other items according to what they recommend.
Hello Roberta- your owners manual should tell you what is to be done on the 30k mile service- if not check on line or call a dealer.
Thanks,
Super Girls Auto