I've played a lot of fox other melee brawl and smash 4. melee is a whole different character so its not really relevant, but in brawl/smash people know to watch out for the upsmash, and if someone is activly watching out for a move it can be incredibly hard to land it. A mistake I used to make a lot, and still do sometimes make, is just getting way to focused on desperatly trying to land that upsmash kill and I get really punished for it. So try not to just desperate rush in for that upsmash.
That advice might not help you too much, so here are so other kill options you can use to open up your game a bit.
Bair is a very very good kill move in general, look for ways to land bair.
Cross over Bair (that is you jump over them and hit them with the bair in the back of their shield) can sometimes work since occasionally they'll drop their shield to try to follow you and punish your landing, if they do that they eat a bair to the face.
Landing a bair on someones shield, either from the front or the crossup I just mentioned, will often trigger the other player to try to shield grab you, its possible to do a fadeaway bair that looks like they will be able to grab it but you land just outside of their grab range and thus they wiff the grab, when this happens you immediately Fsmash them, so bair grab bait fsmash works well.
you can also autocancel the Bair right in front of them on shield and Dsmash as soon as you land, this is a frame trap that works on most characters (by frame trap I mean if they try to drop their shield to do anything to you, you have a frame advantage and your dsmash comes out before their option and they get hit) if they hold shield all the way through to the dsmash though they get a free punish on you, so it can be a little risky, you cant make this slightly safer by landing behind them so they you are hitting the back of their shield. This method works REALLY well against characters with tether grabs who love to spam tether shield grab.
Uair is your other really good kill move, finding ways to land this can really help your kill game out too, there are heaps of combo's into it around kill percents on characters, I wont list them here since I am still figuring them out but you can find these combo's in other places here on the fox boards. one thing in particular I've noticed is that since both upsmash kills, and dash attack sets up kill moves, if you run at a player when they are on high percents they are going to shield because they DO NOT want to get hit by either of those things and they know that at high percents getting grabbed by fox isnt going to hurt them much, so if you run at people when they are at high percents and go for a grab you'll usually get it. Now as I just mentioned foxes grab options when the opponent is high percent are not very good, BUT I've found that if you up throw them, you get them up nice and high in the air, which actually puts you in a really strong position where you can pressure them with uairs (they'll be airdodging these uairs so look to punish the end of the airdodge with uairs, sometimes just doing an empty jump at them will cause them to airdodge and then when that airdodge is about to end you double jump uair and you'll hit them) so you pressure them to the ground with uairs and if none of the uairs hit them you can usually punish their landing with an usmash (espcially if the airdodge into the ground) if they have a good landing aerial what you do is you run at them and then shield next to where they are going to land, if they use an aerial on your shield you can either regrab and throw them back up to start the pressure all over again, of you can do an out of shield upsmash if they are really close, of if they had a longer range aerial you can drop shield, run and upsmash, but this might not work if they dont use a laggy landing aerial, so in that case you'll have to run grab.
Anyways, a bit of wall of text there, just some other options for you, if you just use upsmash you'll be a really one dimensional fox that people will figure out quick and wont have much trouble with, but if you keep trying new ideas and branching out you'll find that foxes killing options are actually spastic and that you will kill people in all kinds of ways.
Also I've noticed that @
DEHF is really starting to figure out all these crazy dsmash the opponent as they grab the ledge stuff, I suspect he will develop that part of foxes meta and then we'll have some sick gimp kill options too.
