The first step to dressing kitties is learning how to cut stuff out for them to wear
then copy and paste another layer on top of the one you are using
"turn off" the bottom layer by clicking on the "eye" which you see on the right in the layer manager
point to point gives you more control
hold down your "alt key" to start clicking
when you have it all cutout save it as a ufo or psd to use for other things
or as a transparent gif if it is finished the way you want it