Hi Debib, To reduce the ragged edges with the Doodle Tool you can reduce the Hardness slider down a little. Even at 90% it will produce a softer edge.
The next version of Ribbet (coming in the next week or so) will allow you to create a blank, transparent image which you will then be able to drag a photo onto (from the photo basket) and erase the parts you don’t want. In the current version what you can do is open up the photo you want to layer onto (i.e. the background photo) and then drag the photo you want to erase from on top (the image/person/item). You can then use the eraser tool on this new layer to put the image/person/item onto this background.