Other than the existing documentation in the product, there's
this thread. How complex are these feats? If they're just text, the existing documentation is quite sufficient. If they need to manipulate other elements, it gets trickier.
Side note, if you really want to Get Good at using the editor, download the Authoring Kit and run through the Savage Worlds walkthrough. Learning exactly how the scripting language and game elements work did wonders for me (although you'll also get a lot more frustrated about all the things you could do with access to the source code).