Help cleaning up

What's the best way to start to teach my 20 month old to help me clean up her toys? She's my first baby. I've tried asking her and showing her how to help me. She helps when she wants to but will other wise make even more of a mess as I'm trying to already clean up the existing mess. I've tried limiting the number of toys she can play with and it still doesn't make a difference. I feel like I spend all day picking up messes just so I can walk around the house easily. It's exhausting and I'm frustrated. When I nannyed years ago the little boy always helped when asked without much fuss. So I assumed I could be the same way with my girl