As you can probably tell from the costumes listed in my signature, it's pretty much all I really do. And I've found that it's actually quite particular. Unlike with anime and video game cosplay, there is an actual item that exists which you are trying to replicate, with a particular fabric, particular closures, and particular seams placed in particular places.
I'd cover things like ID-ing items, where the best places to find reference images are, finding suitable replacements, drafting patterns for items you can't buy or thrift to have the same construction as the original item, identifying a fabric based on it's texture and sheen, so on and so forth.
It might focus a little more on Doctor Who and Supernatural, because that's what I know the best, but I'll try to cover pretty much everything if I can, like Sherlock, Harry Potter, the Hunger Games, Star Trek, Star Wars, Firefly...
So any interest before I decide to submit the panel?