"My Chevy Cavalier has 100,000 miles on it, what does it need to keep running...

...great?"? I know it needs a tune-up...but i'm afraid to go to a repair shop where they will try to up sell me since i am a cute blonde. I haven't kept very good track of the services I've had on the vehicle thus far so does anyone have advice for dealing with the repair shop song and dance?

Keep with the maintenance. Its the same for every car.