Assuming you're playing sheik, ftilt can destroy missiles along with most moves. Ftilt is faster, however, making it the best option. Try and bait out a dsmash here and there by full hopping in like you're going to fast fall aerial him, then double jump. If all goes well, he'll dsmash and you can fair>grab. If he starts catching on try tomahawk grabs, meaning you short hop in, fast fall, grab. CC is easy to beat, just run in and grab. However, be wary of a preemptive dsmash. If he starts putting out dsmash before you attack him, dash dance back and bait out a dsmash that way. Downb should be easy enough to avoid, just notice where he does it and attack after he does it. Depending on when/where he does it, it should be a free punish for you.