Fast-fall. It is the key to connecting sweetspots.
Fast fall, and I guarantee you will sweetspot like, three times as often. f, b, or d airs.
Another way to do it is to shorthop and immediately f-air/b-air. Try jumping with X while holding forward and rolling your thumb onto A. You should be able to sweetspot in the face.
You could also setup a lightning kick by Din or SHFFN-air. (Short Hop Fast Fall N-air)
Oh... Here's a little trick that might help.
You'll notice that there is a point when approaching the edge of a stage that if you, say, do a Din's Fire, Zelda will suddenly move from by the ledge to on the ledge almost instantly. What you do is run off the side of the stage when the opponent is close. Lure them in, since they'll probably come after you to spike. As they get close to the edge, jump and hold towards the stage, and do a b-air (you should hit them at about crotch-level.)
It should be something like this.
Zelda should continuously, fluidly move from point 1 to 2 to 1 to 2 and so on, f-airing or b-airing when near opponent. You could do this for recovering opponents to I suppose.
Usually it's quite unexpected, and works on even the smallest characters. With some practice, you can hold away from the stage after b-airing, so that Zelda gets her second jump back, without stopping. It's similar to the ISJR thing. It's just a continuous motion of moving from South-East to North-West, doing b-airs along the way. You need to be right at the edge for this.
Also, let's say you're coming in from the right. If you wait long enough, (the timing is ridiculous), you can sweetspot f-air to the left, and the opponent will fly TOWARDS you. It's possible on all characters, but easier on large ones. Basically, it's like f-airing a recovering opponent off the stage when YOU are the one recovering.
