Good work out plans for girls?

Hi im almost 20 years old and 5ft tall. I am already slim but I would like to tone my body. I would like to work on my arms legs and tummy. My tummy is already flat but I want my abbs to show more. What work out would help me get that? Also I am thingkin of getting a gym membership with my sister for the summer. We are considering Bally total fitness. Is this a good gym? And waht is the price to join?