C.C.
I tidy up the house before my cleaning ladies get here, so they can clean the things that really need cleaning. I fold the laundry, pick up the kids' toys, put away the things that are sitting out that shouldn't be, put any dirty dishes in the dishwasher, etc. That way, they can get right to cleaning the floors, bathrooms, windows. I have friends whose cleaning ladies do all of the tidying up, too, and I know my ladies would do it, but I'd rather pay them to do the "heavy lifting" rather than the light duty stuff that I can easily do myself.
In terms of what to have her do, I'd prioritize the tasks. Different people want different things done, so just be specific if there are certain tasks that you really hope she does (and if there are things you don't really care if she does or not, tell her that, too). My cleaning ladies asked if I wanted them to do laundry - but I'm kind of neurotic about laundry, so I said no, ignore the laundry baskets! But maybe that's something you'd like your lady to help with. It just depends what's important to you, and what tasks you feel like you want help with.