I play as Robin a lot so here are a couple of my strats.
Don't be afraid to charge thunder in midair.
Casting any variation of thunder midair is useful, especially for pestering and distancing.
A common strategy to avoid ground level attacks is to jump toward the opponent. Robin players will see this a lot as opponents expect thunder and fire attacks. You can jump toward the opponent as they are jumping and cast arcfire. When you cast arcfire midair, its hitbox is harder to predict and can catch opponents in midair as well. If you catch them in midair with arcfire once, jump up and cast another. This combo is easy to land with some practice.
Likewise, Robin can employ this strategy by short hopping over enemy projectiles and attacking with Fair.
On the ledge, you have a couple options. First, you can simple attack as you climb up. Second, you can hold dodge and roll past the opponent (hopefully). Another option is to fast fall off the ledge then quickly jump and attack with up-air. Robin will swing a wide crescent through the ledge and hit the opponent.
Pick up Robin's books. They are very fast projectile items that you wouldn't usually see in For Glory.
If you're falling above the opponent, you can usually hit them by casting Robin's recovery at the last second.
Robin's Dair and Bair are both effective at catching opponents off guard, especially if you pester with magic in the air.
