The black sheet is a great idea and doing them yourself, i got some Pixi Photos done when DD was 10mths... got the cheapest package $200+ and only picked photos i thought she wouldn't sit still for at home... lol
She's a bit of a poser though so the photographer had no problem keeping her still to look at the camera.

When DD was a little younger i used this cool pink blanket she had been given, put it over my bed head and most of the bed, a pillow under her and snapped away.
I threw in some 'random' items like a pearly necklace (clearly fake ) and a cute purse of mine... turned out quite well if i say so myself.

Also try a white sheet etc for different affects, favourite toys.. you name it.

Leah Geisler - Australia | Facebook
Take a look if you like, group of 10 pics in the middle of the page!