>>538537351
Play Lilitales and Monstergirl Quest for inspiration. Basically if you're (mostly) controlling only one character, there needs to be a lot of interesting options. Equipment swaps, moves that can interrupt specific attacks, some kind of resource you can spend that doesn't require you to spend your single turn chugging potions, etc. Don't fall into the trap of designing a huge skill tree, because while planning your build might be fun, the in battle experience will usually boil down to cycling between a couple efficient skills and relying on passives that don't meaningfully change the gameplay.