Practicing lightning kicks against comps helped me to get the spacing down. You can just practice against level ones. Just keep trying until you memorize the distance and height you need to be at. Of course on certain chars, rising kicks are not possible unless they are on a platform. I also like to practice throwing them off the stage and kicking them off stage. It's a great way to practice quick arial spacing judgements.
Up airs on comps are a bit harder since alot of times they won't dodge as much as a human. Play lots of people enough though and you'll find ways to use it. The key is to not just blindly shoot one as you hit or smash them upwards. Blind up airs will usually not get the job done.
If you notice in my video, I will mindgame them into air dodging first and then hitting them. If you can keep them guessing as to when the up air will come out, that's a great advantage to you. Up airs can also prey on opponents tendencies. For example, if you upsmash an ike, what will he do in response, will he challenge your up air with a fast falled down air, will he try to counter it, will he air dodge, will he DI into you, away from you or will he simply do nothing at all? It's all about picking apart their play style and instincts. I know it's hard to do against people you don't know like in tournaments, but if you work at it, you'll be able to adapt to people quickly.