How to be a scarier person

Okay so I'm 15 (girl) and when I walk into a room I might as well have 'dork' written accross my head because as soon as i enter I become the target of teasing and picking on. The thing is, I am the smallest and physically weakest girl in my class, (so an easy target) and I hobble when I walk due to a bad injury a couple of years ago (which is normally the topic of the teasing) and I do not look scary in the slightest bit to try and defend myself, I just get laughed at and teased more. I have practised an evil glare and I can kinda do it. Basically, I am sick of it and I want to become a loads more scarier. I don't mean I want to be the one who does the teasing/picking on others, I mean I want people to "think twice" about what they are about to say to me (or there will be consequences mwahahahah!!)
I have told the teachers about the teasing but nobody listens to the teachers so after the 10th time of them telling the 'teasers' to stop it, they just gave up, which is not very good. My mother is appauled at the teachers.

Please please please help me!

Ps I don't mind if I develop a reputation.

Well it helps to be tall and built tough, but when you don't have that going for you then you have to have attitude. First, be quiet around people: don't laugh, don't smile, don't giggle-- stay frosty around everyone but your friends. ake people always wonder what you might do next, heh heh.

Second, look at people like you are ready to step on them like cockroaches. Don't display any overt emotion.

Thirdly, wear sunglasses as much as possible.

It's all a matter of attitude. Not only think you are a tough b, but when you feel it; that you are tougher, meaner, better than everyone else-- you show it and people will treat you with more respect. Just look at people like Spock, James Bond, and all the other tough dudes They don't act tough, they radiate "I'm a badass; don't mess with me."