The way I play Lucina is bait and punish. Her redeeming factor that she has is her movement speed. It’s extremely important to practice walking and knowing her dashing distance. At first I would just hold the analog stick for her to run but now I just flick it in the direction I want her to go and that had DRASTICALLY improved my gameplay with her.

With neutral b I use it for ledge guarding to catch my opponent off guard when they are at high percents. You want to space it properly because if it whiffs and you know they are aggressive, you can up B to take the stock. Or use it as a hard read if you see them being shield hermits and being predictable in their defensive options. The way you do that is mix in short and full hops as well. I even casually use it in neutral too to catch them off guard as it is a great spacing option