I have three little girls and two older nieces and I get a lot of clothes handed down to me by DSIL/DB, as well as having bits I want to keep from my oldest for my younger two. So at the moment I have lots of clothes of various sizes waiting to be grown into, or for the right seson to be worn. These are all bits I definitely want to keep - I'm already pretty good at getting rid of anything that I don't like or the girls won't wear!
Trouble is I'm not sure the best way to organise/store them! At the moment everything of all sizes is just in a couple of huge bag - but it's practically impossible to keep track of, and I find that the girls have grown out of things before I rediscover/remember we have them... 
I desperately need ideas on how to store them better - by age? by season? and in what type of containers/boxes etc? And ideally some easy way to keep track of what I have (so that next time I see a "bargain" age 3-4 Christmas jumper for example, I remember that we already have 5 and probably don't need any more!
)
Anyone super organised and care to share how they keep kids clothes organised when they're not actively part of a child's wardrobe?!