Sometimes, against slower opponents, I like to propel myself a bit with B-Air, making them think I'll go left or right, then proceed to drift in the opposite direction. You could probably throw in an N-Air to hit them from the side, so they can't follow you as well. You could also hit them with your D-Air just for extra damage, and to pause in the air so an attack doesn't hit you (useful against Up-Smashes.)
With a gyro, you could press the shield button to drop it down in front of your enemy (don't do this against Villagers, they'll just pocket it). While it's spinning, it could hit them and buy you time to get down. Yes, they may grab it, but that still leaves you time to land. Even if they do throw it back at you, you can reflect it with my third and final way to potentially land...
Use your Side-B, Arm Rotor, to disrupt your enemy. I'd use this to punish a failed Up-Smash, whenever an enemy is charging a projectile to shoot when I land to potentially reflect it at them, (like Lucario, Samus, a silly Mega Man, so on and on) or for an unexpected move to throw out when you don't think you can outrange them with your aerials and need to stop them from attacking.
I hate being above anyone in a R.O.B MU, but remember that his N-Air gives him much more options than a lot of characters, too. ^-^