i was messy when I was a kid and gave my mom a headache over it. now i'm the opposite and my 3 y/o dd has luckily followed in my adult footsteps and insists on picking up every last thing and putting it in it's proper spot at every nap time and every night before bed as well. Her room is the cleanest, most tidy room in the house. I don't clean it for her but, rather have her clean it herself or clean it with her. she has no objections to cleaning at this point as she is used to it being part of her routine.
it has to become routine. you'll just have to make a "it must be clean every day" rule. an unmade bed, or stack of that night's homework on a desk is ok... you can't be totally anal about it but, clothes on the floor, food wrappers, or toys anywhere but, where they belong is just asking for a pile to form.
Honestly, since you've tried and tried and attempted punishments and the room is still in that bad of condition I would take everything out of the room besides bed, bedding, and furniture (dressers, shelfs, etc.) I'd stach the truely meaningful stuff (but not give it back to be misstreated in the room again) and give away every single toy and unnessesary personal item. I'd keep her clothes in a seperate room like the laundry room until she can prove they can be kept tidy in her room again. She doesn't need any of that stuff if she is treating it that way. No reguard or respect for personal items, your hard earned money, your authority, or your home. Not to be mean at all, heck, I was the same way when I was a kid. My mom never emptied my room and quite honestly, I wish she would have so I would have gotten the point earlier. it's not too long before things get unsanitary in that situation. As a parent you also need to be in charge of where her daily clothing is going. Nothing she wore that day should land on the floor... that how things end up getting worn far too many times, get stained, or go unused and wasted. She has to learn by you enforcing it on a daily basis. Take it from someone who knows how she is thinking, she isn't just going to make a life change on her own overnight. Also, make sure you're a good example by keeping the rest of the house and your bedroom in the condition you would like her's to be. You probably already are but, just in case you're not, she isn't going to listen to a "do as I say, not as I do" plea.
some may not agree with taking things away and insist it contributes to future issues but, honestly any approach you take can have any number of effects. The best thing to do now is to solve the current issue and do so in a manner that doesn't make her feel bad about herself. A lesson in possesions is in order. You can be kind and snesitive while dishing punishment. Allowing a hoarder to hoard is only enableing. Break the cycle while she's young!
~TRACY, wife to loving dh, mommy to dd (10/05), ds(12/08), 3 kitties, & 2 pups.