Depends on the size of the bin bag 
I have found it helpful to go around and collect all the items by person + type.
Marie Kondo has a suggested order for whatever reason which I have found useful:
Tops (if too many, divide by subcategory: t-shirts, blouses, jumpers,cardigans)
Bottoms (again can divide into shorts, trousers, skirts)
Dresses/full body items
Socks
Underwear
Nightwear
Accessories (scarves, hats, belts)
Clothes with a specific purpose (uniform, sports clothing, swimsuit)
The reason for doing it this way is that you don't have to do it all in one go. So if you're doing your own tops for example, you first sort through every laundry pile and find any tops belonging to you and stick them all in the wash with a colour catcher if necessary. (Or, you can sort them dirty if you need to - in this scenario, I would look ahead to the next category and wash all of those).
Then take all tops from your drawers/wardrobe. Then go around the house checking to find any lost or forgotten tops. Now you'll have every single top that you own and you can lay them out on your bed or on a clear section of floor, a la the warehouse.
It's helpful because you can then see - OK I have enough tops that I could wear a new one every day and not do any washing for 3 weeks (or whatever). Do you really need/want/wear that many? It should be fairly easy to identify the items that you know you gravitate to and tend to wear as soon as they are clean, and the items that you tend to avoid wearing. So you'll have some easy keeps, some easy donates, and then you're left with everything in the middle.
If you have enough easy keeps you might just declutter everything in that blah middle space. If you don't, then you could look at items which are similar e.g. do you have four black t-shirts? Do you NEED four black t-shirts? OTOH do you have four black ones which you wear, and then three coloured ones which you rarely wear because it's too hard to match them to things?
I have also found it helpful to basically pick a colour palette and try to stick within that, as I like wearing colours but find it hard to match them.
Once you have sorted through all tops, you know tops are done. Which means you can put them back away and not worry about them. When you next go to sort through bottoms, you are not looking for tops.
For kids' clothing I also like sorting by type of item, because it means you can instantly assess which clothes are too small. I mostly ignore label sizes and tend to pile up t-shirts, trousers, LS tops etc according to size - then I get them to try on one of each pile and sometimes I can discard an entire pile at once because I can see it's all too small.