Jiggs ground game (worth using)
Dash attack
Grab
DACUS
Tech chased Fsmash
Jab or Ftilt
That's the gist of it. I didn't go into specials because, well, I'm lazy and hungover right now. Those are her viable (?) options. If you do anything else, unless you've come up with some revolutionary new way to use it, chances are you're doing something wrong.
Dash attack clashes with a lot of attacks, from what I've seen it tends to have the best "priority" (priority is based upon percent of the moves clashing. Not explaining it in detail, go read up on it somewhere else) as it will stop a large amount of ground moves, a non diminished dash attack will clash with moves that do as much as 22%, so practice up. It's reliable as hell and the endlag after clashing is so nonexistant that you're often in good range afterwards. Plus it can kill. That's why I have it first on the list, as I think it's her best option.
Plus her fox trot makes up for her slow speed, and this becomes all the more viable.
Her grabs all do 10% (read: awesome) and although they don't set up, they are great. Grab a shielding foe, follow up after an aerial. They're absolutely great combo finishers for on the stage, and can set people off the stage if your / their back is to the edge. I'd probably put them second, I use them A LOT. You should too. A LOT.
After certain attacks, a DACUS is a great follow up. Learn the range of it, and how to best use it. You can over charge it and punish airdodgers too. It can sneak in or laggier moves (say, attempted zoning.) It can kill if at high percents, and if not, set up for uairs or other aerials or generally just give you space. Do this. It's good when used correctly.
Tech chased FSmash, while unreliable to a certain degree, when you read your opponent correctly this will probably kill them. You know the basics for this, I assume. If not, go read Illinialex's guide. Hell, even if you do know this, go read that guide. It's a good guide. You'll love it. If you've already read the guide? Read it again. A+
Jab or Ftilt can be used for spacing (or jab infinite if you can lock it down) but generally, the grabs are MUCH better and give you more room. Unless you want less room, which can be a possibility. I don't use this frequently at all, but jabs/ftilts can bait shielding opponents into your shield grab, so I can't completely dismiss this.
Overall her ground game sucks, but learning how to use what's there is vital. Have fun with this info, guys. Especially the dash attack, I never see you guys use that.