How do you get over being jealous?

i have this really pretty older smarter cousin who is 16, and she has been selected to be a teen queen uk model ! im so jealousy of her she has everything, blonde curls, flawless skin, perfect teeth, size 6 figure, the gorgeous boyfriend, the rich family, stage school, model offers ! she is even nice to me but i never talk to her because im so jealous ! my family all say she is the beauty of the family and always go on about how she is going to be a star ! its quite hurtful when your whole family say your cousin is prettier than you, especially as their are only 2 granddaughters me and her! im so pathetic and i want to let go of this jelousy but i don't know how? please help