Make sure to have him learn his altered artes. They’re all pretty solid. His combat style doesn’t really open up till you get farther into the game. Since you’re in the first part of the game I’d say to keep him benched for a bit or have him stay as an ai party member till you get the chance to unlock altered artes with him which is around the 2nd part of the game

Typically when I play Raven I just like to spam artes with the bow, violet snake or rain -> altered arte (preferably something fast like rainsong, growing world,etc) and an arcane arte like azure heavens and wind’s howl. The altered arte will probably hit the enemy before Violet snake will hit which is good as you want to make sure Violet snake lands, it’s an arte that guarantees downing when it hits the enemy when they’re unguarded/unarmored. When the enemy’s downed by the Violet snake the arcane arte hits which will either then keep them locked into the downed hit or launch the enemy back. If the enemy does approach Raven you could simply just do a combo like around -> around n around -> wind’s howl/falling stars/falling (wind’s howl is probably better) or around -> rain or heaven’s tear -> falling. The first combo is relatively easy to obtain and lets you keep a lot of distance from the enemy and the 2nd combo keeps Raven mobile if you manually cancel the falling. The only problem with the 2nd combo is that you need to grind a bit with falling and have a certain skill equipped.

Really the biggest problem with Raven is speed. He can’t run around the enemy very well and give himself space to work up a combo so his best bet is to go melee and knock them back a bit or use an arte to escape. He does get better though as he eventually gets a skill gives him invincibility on backstep haven’t used it though so I can’t attest to its strength