At 2.5 I think your best bet is to try and make things fun/into a game. 'Let's put your coat on - ooh you're like an octopus, one arm wriggle, wriggle'. I sympathise because ds really doesn't like getting dressed at the moment
- adn we DO have to be somewhere... It's all about experimenting and finding out what works...
Soemtimes I say 'right, ds, let's put your trousers on your head!', he giggles and says NOoooooo, 'on your nose' 'noooo' (all the while, putting them on him). Lots of hurrah, you're all dressed when it's done.
Choices can sometimes work too - 'dd do you want to put your coat on, or mummy put your coat on?'
or ignoring tantrum and talking about something else entirely (while you put coat on) 'hey, dd what shall we look for in the park? I'm going to look for a big stick!'
(I) Try to think of it as you have 'won' the battle already (simply by being the grown-up who will actually get her way) so you don't need to be heavy-handed or horrible about it. And it doesn't matter if they think they have won. All the better IMO - then you both win!