Help at wit's end! How can I get my older DD to be nicer to her sister?

[stumped]

I'm at my wit's end, and the school hols haven't even begun...
My older daughter is horrible to her little sister (9 and 6). Number 2 absolutely adores her older sister, loves her to bits, shares her sweets and toys and would generally do anything to get no 1 to like her.
No 1 can be really mean, selfish and generally quite horrid. I don't know where she gets it from, I've tried so hard to teach her to share and be friendly and lover her sister.

It's got to the stage where I don't like DD1 very much any more because I can't stand the way she behaves and it causes so much tension in our house.

It's a viscious circle and I can't seem to find a way out.

No Dad around, he died when they were tiny, so it's just us three girls and frankly I'm so tired dealing with it on my own I just don't know what to do...

any advice welcomed! Thanks

That sounds tough

What strategies have you used in the past to deal with it? Is it a fairly recent thing or has it always been this way?

Firstly remind dd1 that you are the alpha female in the house and that she is a child.

You should also emphasis the importance of their relationship as sisters. When friends fall out sisters are always there for one another. That type of thing.

And this sounds a bit crazy I know but it works. I've always emphasised that ds1 and ds2 are on the same side, even if that means I'm the baddie (I'm a grown up though so can deal with being unpopular). For example, when ds2 was first born and ds1 had been naughty, I'd put ds1 on the naughty step and ds2 in his naughty cot. I was the common 'enemy' (I have a really good realtionship with my kids by the way, honest) but this made them join forces so to speak and created a really strong bond. Get them on the same side.

It does sound completely crazy but try being mildly unfair to dd2 and see how dd1 reacts. She needs to be protective towards her sister rather than resentful and this could work.