Here is a simple idea to inspire you. It does not have to be expensive or complex at all and you can personalise this by using different colors, name of the baby and whatever you like.
What you will need is a dollar shop frame . I was lucky mine came with the decorative backing with the heart cut out. But of course you can do that yourself and use some thick card.
I used a rubber baby but you can use any baby doll you happen have . Clothes are also optional. A little nappy is very easy : just fold a piece of no fray fabric round the baby.
My blanket is knitted but you can use a piece of fabric or lace or knit or crochet a simple blanket. Fabric stiffener is used to prepare the blanket.
Lace or braid is nice to put around the cut out shape but is optional.
Dip your blanket in fabric stiffener. And squeeze out excess.
Wrap your the board with the heart shape in plastic and place the blanket on top of the plastic and shape it. Leave to dry.
Remove plastic and glue blanket where you want it to go inside the heart shape. Glue baby and decorations in place. Add the lace bow.
American Miniaturist will publish an article about this project as well. In the article there will be more details about this project, patterns for the hat , blanket and tiny bunnie . So look out for the article as well. Not sure which issue it will be in yet.