Is it good to DJC with the Control stick? I find it much easier to DJC with it. :3
Oh, remember that your upsmash and downsmash aren't really smashes, mostly just extra tilts. Neutral A has great knockback, practice the PKT2 (when you hit yourself with the upB) because its the best thing you have. Don't approach with Dair, its too laggy, his best killing moves are back throw and bair (when you hit with the sweet spot). Also, people might get scared when they see the bair, because its so sparkly. His Uair is so awesome to juggle, I love it. Also, I think the upsmash and downsmash is good for juggling too, if you hit them with it, its a bit weird to get used too.
Try using the PKT as a projectile, when you are grounded, but don't use it too much. Its up to you to tell if its time to stop PKTing. Of course, side smash is great, just try to hit with the tip. Wanna try Meteor Smash? Its not that good, but at least he has one. Also, try spamming dtilt a bit, but not too much. :3
I second Ness, but sadly I'm not as good with Ness as I am with Doc. Ness rocks though. I might just change my username because of him.
EDIT: Oh, you probaly obviously know all that... Well, don't use downB, its a waste of time. Everytime you tryed to do it it was too late, fox's laser is too fast.
According to the super long ness guide, the best way to get a combo on fox is to upthrow and djc Uair or fair if they DI'd. :3