I agree with Harriet about doing the easy stuff first. I used to try going through one box at a time but found I would get caught up with particular items, agonising about them, unable to move on. So now I do 'sweeps'. I go through stuff only looking for one type of thing at a time. The first is 'obvious rubbish' (this depends how messy it is to begin with of course... ) which includes any broken toys. The next is 'separated toys' so things like animal figures, Lego pieces etc which have got spread around the house and I know we are keeping, so these all get pulled out and put in little piles next to me (I do most decluttering while sitting on the floor) until I'm done, when I put them all in their places. Then I might do pens and pencils, then 'stuff for charity' etc. While I'm doing this, anything I'm not sure about I just leave for now rather than worrying about it. This gradually whittles down the amount of Random Shite. On a really productive day recently I got about 7 boxes reduced to one doing this method. :)
I might do some Digital Decluttering today as I'm not really up to the physical stuff! I have been deleting some apps on the iPad as just like real toys, too many means it's harder to focus on the good stuff. Also, now we are starting to think about Christmas (sorry :o), I am going to go through my many Amazon wish lists. They are huge (and divided into about 10 categories) as I tend to add stuff without thinking - partly thanks to their recommendations/'also bought' type widgets, but also due to MN! So many things get recommended on here and I tend to just hit 'add to wishlist' rather than actually considering the item there and then. I don't go on Xmas bargain threads anymore and I am going to delete lots of the items now.