This post is mostly for Hubby who has run out of ideas for getting our children to tidy up, but if it helps you too then great.
Tip: Tidy up often- As I said in a previous post, it's a lot easier for a child to tidy up throughout the day, then doing it once with a massive pile of toys.
Tip: Start young with the expectation that like any chore they are a part of the house/family and have a responsibility to participate in maintaining the house. How young? If they can move toys from one room to another, they are old enough to tidy up although the amount of supervision/direction will change as they age. My motivators won't really work with 18 month old child, but then they should be able to tidy up by the "one rule." Basically it's mimicking you. You put one toy in a basket and then they do it. Repeat.
For the older set.....
1) Have something you are planning on doing afterwards- "Hey, guys, let's tidy up and then we'll have ice cream afterwards." or go to the library or go swimming or go to the playground/park etc. But if they don't end up cleaning up, then don't go. Make sure these things are not stuff you have to do. If you already planned to meet up with a friend at the park, well, I hope you tell your friend why you couldn't show or perhaps that shouldn't be a motivator.
2) Sort them by....- My children love to sort by color, but you could sort by size, shape, type, and material. It helps break down the task of tidying up into a small less overwhelming chunks and before they know it they've tidied up.
3) Use counting....- "Let's see how many you can tidy up in one handful." "10? Wow your hands are so big." or "I need you to pick up 20 legos. I bet you can do that."
4) Pretend play- I've pretended to be a toy eating alien and my children have had to "hide" their toys from me. If the toys have been shoved under beds or other nooks and crannies, then you could be archeologists on the hunt for artifacts from an "ancient" civilization. If your children are into super heroes, you could also pretend that the toys are people that they are having to save. You get the idea.
5) Racing- Put the toys into piles one for each child or if you only have one child, yourself and said child. Then race to see you can put the toys away the fastest. Or set a timer to see just how quick you can clean a room. Make a chart and see if you can be faster next time.
6) Toy Time Out- If you are struggling to get your child to tidy up, a last resort motivator can be giving them a particular time to clean and whatever isn't tidied goes into toy time out. This is also great for knowing which toys they really cherish and which ones can be weeded out. Right now my children have a colossal amount of toys in toy time out. They've managed to get some out by tidying up when asked. If tidying up seems to be an overwhelming task for your child (and yourself), toy time out can help you pare the amount of toys to a more manageable amount.
7) The Dyer Sheet/Fabric Softener/Laundry Fairy- This one I read about in a children's book- Frankie Pickle and the Closet of Doom. It seems to something to use as a long-term motivator. The parents in the book couldn't get Frankie to clean his room so they let it go feral with the caveat that 1) he couldn't let it escape his room and 2) he had to deal with the consequences. It's quite funny, so I won't spoil it for you. In the story the Dryer Sheet Fairy would take his dirty clothes and magically clean ones would appear in his dresser along with a dryer sheet on his pillow. This stopped when his room became a mess. You could have the Fairy write notes asking that laundry go in the hamper in order to have it washed by the Dryer Sheet Fairy. She or he could also leave behind thank you notes for putting them in a hamper. Or to motivate the child to put their own clean clothes away leave a laundry basket with a note. This is something you could implement with toys too. One beloved toy could be on an adventure, and your child may have to figure out where he has gone. In the process he could ask your child to tidy up so that his travels are easier.
Hope these ideas help, Hubby!
8) Use "Magic"- I forgot about this one earlier. Your children can be magicians and make the toys "magically disappear." You can also zap your children with "cleaning magic" that makes them stronger, faster, etc. They can become the super heroes of clean.