Thanks..I'm not creative at all, so can't help there. Just use google and search your fictional name...you'll find images that'll help get you started.
One important thing to remember is that ootp does not resize backgrounds so your background has to be the same resolution as ootp is set to use for best results. Mine is 1920x1024.
Easiest way to get started is to goto any teams schedule page and take a screenshot to use as a template and save it.
When you add layers to it, adjust the layer's transparency so that you can see ootp's screenshot. Now you can line up all your layer images so that they don't cover up any ootp data you don't want to hide.
Remember to reset your layer(s)transparency to none before you merge them and save the final pic. Make sure your ootp's tempate pic layer is not included in the save.