I main Fox, and I know how hard it is to K.O... Have you tried D-Throwing and then F-Airing off it? And do you use blasters, cause they're really horrible. They barely rack up any damage and by the time you get to 10-15ish, they already landed a hit. I try not to rely of his dash attack too much, cause it gets obvious after a while, but when you do land it, try any aerials, B-airs are harder to use but more effective, but Up-airs and F-airs are also good. Try to catch them off guard when you're standing in front of them by short hopping, n-airing, then fast falling, because it usually hits and can do damage besides just rolling away. Fox's recovery is okay, but with stages with flat sides, always try to wall jump and up-special make the ledge grab more precise, cause the end lag will probably result in you being knocked off again. His side-special is better used in recovering, especially since he doesn't go into a fall state anymore. At high percents, you might even be able to knock your opponent far enough to recover. I guess you can also use his F-throw, dash attack, and f-air combo, but it's kinda hard to do. Never use your reflector for recovering or stalling, the ending lag and start up time increased.