It'll help if you can get her on board, so I'd do it together, although it'll take much longer as a team effort.
Get some stacking drawers so there is a specific place for each kind of toy. Label each one with a photo and word label of what's in.
I found that tidying weekly/monthly left too much of a mess in between. It was easier for us to have a ten minute tidy every day to keep on top of things, then a proper clean (vacuum, polish etc) less frequently.
I wouldn't expect her to be able to tidy on her own. My ds with AS is 10 and I have to sit on his bed and give guidance/support or he can't manage. He gets frustrated at his own distractibility if he's left on his own so it's not worth it. You have to have realistic expectations of what your child can manage, supervised and alone.
Photographing the tidy room might help, if she likes her room to be tidy. If she likes a bit of clutter, comfort of having her familiar stuff around her, she might not be motivated by the picture.
I now realise that too much on display is distracting to my ds so we have an agreed number of toys out on shelves at any one time, if he gets a new eg Lego model then another has to be boxed up. And toys always have to be put away after playing otherwise he can't focus on dressing etc if they are left lying around.
It's an old cliche, but it really does help to have 'a place for everything and everything in its place'. There's a logic to that which our Aspies like.
HTH.
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