I.
Don't pass any negative judgements about someone else's appearance. Just don't go there. It doesn't matter how ridiculous a person looks to you, or how many people you respect are indulging in their inner mean girl, their body is not your problem. And it's not your right to make it a problem. It should not concern you in any way and making negative comments about someone else will only reenforce the negative feelings you have about yourself. Gaining a feeling of empowerment from putting someone else down is a myth. It doesn't happen. I should add that finding comedic value in putting someone else down is a poor way of behaving and can only provide testament to the way you feel about yourself.
I know all of this because i used to be a nasty little Lamb. I'd be the first to comment on the way someone looked or spread a vicious rumour. When you have low self confidence it becomes so easy to pick out the flaws on others. But all it serves to do is make you hyper aware of your own flaws and the people who may, in turn, be judging you. It's not a case of "haters must be jealous." More that those who chose to be hateful towards another person's appearance usually have deep rooted issues with their own appearances. This isn't an easy habit to get out of, but it's well worth trying. If you catch yourself engaging in, or about to engage in making nasty comments about someone, remind yourself that it's not your problem. That you shouldn't expend any more time or energy just to concern yourself with a body that does not belong to you. Apologise to the person you're with (even if they're not the person your comments were direct towards), or ask them not to encourage you. By not scrutinising the appearance of others, you can reduce the amount you, unconsciously, scrutinise yourself.
People who push their negative feelings onto those with the opposite type of body are just as insecure. "Real girls have curves," and, "Boobs are like soda, no one likes them flat," are just, if they come from someone who identifies as a female (because misogyny is a whole different, nasty ball park), the manifestations of their own insecurities. I used to be guilty of the, "I'm flat chested and very insecure about it so therefore massive breasts are disgusting. Who would want saggy tits, or large nipples, etc." It's very easy to convince yourself that you own those opinions, when in reality you're just desperately searching for the negatives to bring everyone down to your level. Faking confidence by hurting others is just as damaging to you as it is to them.
And likewise, if someone tries to pass judgement on you, to put you down for your appearance then remind yourself, and them if possible, that your body is not their problem and their negative opinions are not valid.
Other posts in this series:
*This "commandment" is only a suggestion and i in no way pass any judgement on those who chose to embrace different or contradictory behaviours. This is purely something that i, personally, find helpful towards being a more positive and confident person. These are all my own opinions and do not have any scientific weight behind them. I respect everyone's right to an opinion and understand that my own opinion should not apply to everyone else.