stop being jealous

I really hate jealousy, and what it does to other people. And I hate it even more when it seeps into my own mind, and fills me with doubt and insecurities. It’s not really that I hate the people I’m jealous of- more that I begin to hate myself, which is just as bad really.
My sister, for example, is horribly popular, not only with people her own age but with my friends as well, to the point at which I feel as though I am second best in the minds of my mates when compared to her. It’s enough to make a shy girl like me feel positively unwanted.
But I don’t want to wallow in self pity. I know it’s the worst thing I can do. But somehow, I can’t help it, and it’s getting me down. And knowing that all this pain stems from the jealous nature of my mind makes me wish I wasn’t like that. I want to be care free, happy-go-lucky.
I want to stop feeling so downright jealous, and accept me for who I am.