I am cursed with shaky hands and the inability to sit in front of a computer for long, so I use my iPad a lot (not that this isn't a struggle with mouse too). Placing items on a pet is hard, especially when it's items that need to be placed pretty much pixel perfect. The shiny border, while showing what I have selected, obscures part of what's going on below and makes it even harder to place things right, so I'm always selecting and moving and desselecting for way too long than any sane person should.
A simple solution to this I think would be arrow buttons. Up, down, left, right. If you click them your item moves one pixel to the side. The arrows themselves shouldn't be on the item like the front/back/flip arrows are, but rather on the border of the canvas to give a clearer seperation and also to not make phone users cry. So you can move your item freely into a location and then use the arrows to get it in the perfect spot. What do you think?