The most important thing is to have her move at a comfortable pace. Don't push her to learn too much, too fast, or it might not be fun for her.
For recoveries, she should almost always Skull Bash first before using her double jump, unless she's close enough to the edge to jump to it or Quick Attack on it right away. Don't use Skull Bash to attack. It has too much lag, little damage, and poor knock-back unless it's actually charged. Which means it will be predictable and shielded or dodged.
Teach her Aerial approaching as well as Ground approaches. See if she can Short Hop Forward Air well to approach, DIing back if you come up short. The idea is to be able to Short Hop Forward Air, but then land more or less where you jumped from, just by DIing. It gives you a good practice for control in your Aerial movement, and would be the only difficult DI to perform. Since the only others are DIing forward into the target which is if you connect, and Fast Falling, which isn't suggested. Your goal should be to maintain your body inside the target('s shield) for the entire Forward Air. Intercept Aerial targets with Neutral Air. It has good knock-back, but requires good forward momentum. You need a running start, and then you have to jump into them. You can practice better Aerial Interception this way, hitting people that are falling, jumping, or even just standing on the ground. Of course, targets on the ground can Shield your Neutral Air. You want to pass through the target, and not land in front of them since they'll be able to Shield Grab.
Rack up damage on Ground targets with (Down Tilt ->) Down Smash, Up Tilt. You can rip through Shields quite safely with Down Smash, and Up Tilt Juggles easily early on. Spacing Forward Smashes is something to work on. You never want to be too close, and you should know and be comfortable with the reach it has. Up Smash as well can be used to kill, but it's potential is more useful in getting a target into the air to be Thundered. Hyphen Smashing (Up Smash out of Dash i.e. C-Stick Up out of Dash) is one of the more important things to do here. Everything else is spacing and timing.
Quick Attack can be tricky for newer players. They tend to have issues getting the second jump to come into play, and then directing it properly. I've played Pikachu and I still have some issues sometimes getting a second Quick Attack to kick in at certain angles. Target test wouldn't be a bad place to practice. I wouldn't suggest teaching her Quick Attack Canceling quite yet in any case. Maybe after she has a good feel for her Aerial Approach.
Hundred Man Melee isn't particularly good for practical use though. It can teach her what attacks have the best knockback though, of course, you can just end up spamming Thunder through the entire thing.
. Otherwise, just have her sweetspot the ledge with either a skullbash or short quick attack. With the new instant ledge grab it shouldn't be too difficult.
