I've spent the last year decluttering, and never ends!!
I had a car-boot sale, got rid of loads of stuff and made money.
Filing cabinet - I got one really cheap (and already built - ex-display) from Ikea Bargain Corner.
If you have any outdoor space get a cheap shed (tin or plastic, but with a floor) box up all the stuff you want to clear out, but can't bear to chuck and put in shed. Resolve to sort this shed out next spring. When you do so you will realise you don't need or want any of it, and sell it at the car boot sale.
Vacuum bags from Lakeland to store your old clothes.
Get rid of the plastic shit. They don't play with it.
I spend bloody hours and hours yesterday 'tidying'.
Step one - go round room by room and move stuff to its proper room.
Step two - one room at a time, sort it out. Don't stop until its done. Phone for pizza if necessary. Christmas is looming, it is only going to get worse!!
The washing? Either do it one day a week and keep one set of clothes for 'Sunday best' as they used to in the old days or accept it is part of your life. We are a family of 6 and I loath putting the washing away. Its a massive job with no sense of satisfaction at the end.
Good luck!