As kids get older, the hardest part of keeping homework organized is the long term assignments (big things that might be assigned a month in advance) that run in the background at the same time as the daily assignments. The long term assignments reliably get forgotten until they're almost due = late night, no sleep, panic...
Here's the plan. Get out a white board and have your kid write down everything that got assigned that day, whether it is due tomorrow or next month.
Things that get completed, wipe 'em off. If it's not done, leave it on the board.
The next day, get out the white board. In available space, write on there everything that got assigned that day. Wipe 'em when they're done, leave 'em on if they're not. In this way you'll always have all the assignments in one place, right in front of you. Easy. It should also be obvious when things are getting out of control -- if the list is getting huge.
An important bit of advice. Last year, when Drew (my son) entered high school, the school conselor told all his kids to use two hours a day for homework, every day, even if they don't have two hours worth of work. If the homework is done and the two hours aren't up, put some time in on long term assignments, read, work on another project of your own (scouting merit badges, for instance). The counselor said the kids don't always go for this, but he guaranteed straight A's with this method.
I got lax about it, and in the end, they are Drew's grades, not mine.
The first quarter we did it and Drew got straight A's. After that, Drew didn't want to do it any more. Did he continue to get straight A's? Well, no. He did not. Now, we're in experimental mode. We're doing the set-aside time again this quarter and if Drew gets straight A's, he says he'll adopt the method.
As for doodling on the white board: purely optional.
I did the doodling with Sharpie markers on a white board I bought at CVS. Here's a funny thing about Sharpie markers on a white board. It's permanent, except, if you write over the Sharpie art with the white board marker, then wipe it off, the Sharpie art erases. I found that out by accident and then tried it on purpose, in the swirling vortex, for instance. Weird, huh?
Update: I presented the white board idea to Drew and expected something like, "I already have a planner from school and I write everything in there," or, "I can remember..." Well, I got no argument. He said, "Sounds like that'll work." We used the white board, and guess what? I think it is going to work!