I'm a big fan of www.flylady.net She's awesome! It's totally revolutionized how I handle my home and business maintenance/cleaning.

With the kids I let them use a bin of toys at once...we have 12 bins in the playroom. Make a mess and play with one bin and then we tidy it up before we switch it up. I also help them tidy...and give specific jobs. "Sarah, please pick up the fire truck and put it in the basket!" and then another job when that is done, until the place is tidy. I find they respond better when I model the behaviour that I want to see...cheerfulness, and helping.