not easy - just a matter of time ... but power and moisture = corosion ... so first job is to switch off, remove battery.
and leave until dry.
you have tree options ...
leave it somewhere warm - (airing cupboard) - not hot for a day or so
buy dessicant gel - pack in cardboard box
or - this isn't a mucky take honest
get a small cardboard box ... wrap phone securely in kitchen paper - put a layer of rice and cooking salt in base
put phone on top
cover with more salt and rice ... leave.
it's almost as good as sillica ... and should only cost a quid or so.
but the important thing is don't switch on again 'till dry