This is all really helpful, thanks.
Aloha, prevention is the best, I agree, and included in that is good sleep, full tummy etc. Actually the only times dd is seriously not cooperative is when she's tired. But that does happen sometimes and so then has to be dealt with.
expatkat, sound advice! I do avoid no's in general. And as for throwing things off the high chair have now got her to either eat something or if she doesn't want it to give it to me and not drop it, which I thought was rather miraculous after months of chucked food and drink!
jimjams, I'll try that counting thing, that sounds good, I've never thought of that.
FairyMum, it's not always possible to avoid things though, is it? Sometimes I have to take a bus journey (dd's particular hated event) and keep her strapped into the pram. It can be hellish. Weird how some kids zone out on the bus and others get really fed up.
Gumboot, yes, it works sometimes for me, the distraction thing. But my little darling has a particularly good memory so even if she'll accept the distraction temporarily, after a moment or two she's back after the thing she wanted originally!
I realise that 17 months is really too young to start giving explanations. But sometimes I get a sense of how frustrating 'rules' must be. For instance how can dd work out that it's ok to walk around home / playgroup and pick up and fiddle with whatever she wants, yet when she's walking outside she can't pick up stones and dirt (which becomes far more appealing of course as it's 'forbidden'. And why do I say she's clever for pouring water from one plastic cup to another in the bath, but 'naughty' if she pours it on the sofa? I'm just a bit confused as to how to make these distinctions clear to someone so young.