So I read the guide and there's no mention of Uair's awesome use in doubles so I thought I'd post about it (maybe it's obvious, if it is, pay no mind).
If you can predict the trajectory (sp?) of your partner when he's sent flying due to a smash or whatever have you and you're below him, then just uair and stop him from dying. Since Uair has some sort of gravity of its own, it stops all horizontal momentum. I've done this to save my partner at 180% from a full charged Snake fsmash. It works wonders.
Just be sure it's your partner, otherwise you'll be saving your enemies!
p.s. I don't think I have a good video of it, but I've done it a fair amount of times. Go try it if you don't believe me.