My 6 yo is lego-obsessed and is into putting together his own creations as well as more advanced sets. I'm in the midst our own lego organizing project and here's what I've done:
- decided to sort by type vs color
- found printable labels on pinterest and labeled drawers on a couple of those rubbermaid plastic drawer units
- covered the top of our old, unused train table with lego base units (looks kind of like this
http://www.gracegigglesandnaptime.com/make-lego-table/)
- repurposed a plastic expandable file for instruction booklets
- dumped all pieces to be organized in a basket that goes under the table
Now it's my son's job to spend a little time each day sorting the pieces in the basket into the drawers. He likes doing this (but not as much as building), and it was only a couple hours upfront work for me. He's already using the sorted pieces to make new creations, and putting unused pieces back in the basket to be sorted again. I got a ton of ideas from pinterest. Next I plan to take an old ikea leaning bookshelf and put base plates on the shelves so he can have a rotating display in his room.