L.J.
Hi A. - you aren't alone!! I am pretty organized now, I have a 4 & 5 year old. The advise I can give you, is dejunk! Take it one room at a time. Get rid of the stuff you don't need & don't use. I always find the best time for dejunking is if I am in a bad mood, sounds strange, but it works. You will be pitching stuff and organized before you no it. Tackle one room, or even one area at a time. Then only the right things go in that space. Get the kids bins for their games, puzzles, all those little toys. Then have them put their toys away and move the bins out of the family room. I keep theirs either in the basement or the garage. That way they are only playing with certain toys at a time, and not a whole load of stuff that needs to be organized before putting it away. I keep all the cars and wheeled toys in one bin, all the art supplies in another, all the dolls/clothes in another and so on. If I run across a stray piece I put in a bag and have a place to go to - instead of it sitting on the counter and getting lost.
I say everything in its place, and everyone needs to pick up after themselves. It took a little time for us, but it is working!! The kids have seperate shelves on the bookcases for their own stuff, DVD's etc. When its time to clean up, they know what to do. I hope I have helped in some way! Let me know if you need some help!!!