How do I lose weight/tone up?

I am 18 years old, 5 foot 4 1/2inches ans weigh 124 pounds. I am considered a peitete girl. Tiny arms and small boobs, BUT I have a larger butt which I like but with a big butt comes bigger thighs which I HATE! Does anybody have any advice on how to slim my thighs, tone my butt and flatten my tummy a little? Any workout routines or eating habits? I would like to be between 115-118 pounds! No less or I my look to skinny!! Thank you!