i hate myself, i need to change? help!?

you mention your older sister seems to have a horrible attitude,
I don't think there is much you can do, really. You also mention your younger sister adores her.
It's not about you, and you cannot change them.
It's like my mum prefer to ignore me and my father provoke me at times,
and they don't understand me and I can't help it.
You might want to ask your older sister why she treated you that way.
Or you could talk with someone else about it, e.g. your friends
you mention nobody like you, but that might not be the case, it's just the people who are close to you, especially family members can have a strong influence on you, which makes you feel that way.
If your family not like being around you, it's their choice, and has nothing to do with you, you have got nothing to feel sorry about,and you don't need to deliberately try to change your attitude towards them. I tried to change my attitude towards my family but it just won't work. Trust me, it is not working.
People do things for their own reason, and you cannot stop them from doing those things. There are many situations where you cannot stop a bad thing from happening, but please don't blame yourself because it might simply be a mistake that cause it to happen, and nobody knows how to deal with it beforehand. If you can find a way and if you do know how to solve the problem, try your best to solve it.
what is making you depressed? try to find out why. Talk to your friends about it and see if anything can be done to solve it. If it cannot be solved simply turn away from the source or try to turn your attention to something else. If you can, try your best to find where the the problem lies, talk it through, try to think of any possible solutions to solve the root of the problem.
Can you have a chat with your friends or teachers? If you talk it through with them you might come up with a solution.
If you have an opinion on near abouts everything, you can keep a journal for that. You can then share your thoughts and opinions with your friends. Try not to moan too much, but moaning can mean showing compassion and sympathy for others, which could be a good thing because there are times when we need someone to care about us. It's natural to think you are right about something. In fact I think it is hard not to think that way. Do what you feel is right is okay, but try not to judge others. There are times when you are arguing with someone, when other people believe they are right and you think you are right too, but I think what you think is more important then what others think of you. Sometimes you could be right, it's just the others don't understand it or they don't get it.
If you want to be right just do the right thing. Consider what others said, but no need to take it personally. If things went wrong and you know you've done wrong but you still want to be right, just stop being like that and correct the mistakes and do what you think that is correct.

I lost 60 pounds, I didnt even attempt until eventually human beings all started commenting me which replaced into mind-blowing. that they'd ask how. I informed them watch what your ingesting and workout,thats all. yet I in elementary words began to adhere to by with this even as i realized the arrogance I outfitted from human beings telling me how I looked!, you would possibly want to do not forget that you cant only give up. because each and every little thing has thier own steps in achieving it. you want staying power and dont get all stuck up and mad in the adventure that your staying power isnt operating, because then your probable going to give up by technique of comforting your self with the point!. So the subsequent time your feeling undesirable about the way you seem Take a step back and say to your self i visit attempt this.. because you could.! what makes you imagine you cant? something is plausible=) What I used to do if i needed to shed weight i might want to say to myself. your going to sense better once you're making the right decision.. and also you know ways that feels!, so it replaced right into a self belief booster. i replaced into pumped when I knew i might want to do it! Its large=D. Take er step by technique of step and dont enable your self be dragged down by technique of anybody who you thinks seems better. and they have something you dont

You have an opinion about stuff. Is that so bad?

Maybe, instead of trying to keep your opinion to yourself, you should just work on the way in which you present it to others. Be nice about it and try opening up your mind to allow others to sway your opinion - if they have a point.

Good luck. It's nice to see that you are trying to improve yourself. You may be "hard work" now, but you seem well worth it.

And on a side issue, I beg to differ. You can most certainly take a picture of a personality :-)
http://www.flickr.com/photos/peopleofthesouth/7882529916/in/set-72157631451020334