Ornit has a couple of good dressings based on lemon. The quantities are a bit vague but the taste is good.
Aviva used to organise big dinner parties in London. 20 South Africans, Galit and me. She did all the catering herself. Everything was fantastic but I only ever managed to steal her recipe for salad dressing before she moved back to South Africa.
Once at Sean and Sue Dick’s their brother in law Ken – a professional chef – gave me some advice on Vinaigrette. Apparently 1:2 vinegar to oil is classic French, whereas, 1:3 is classic Italian.