I like to personalize the spell effect my wizard Kiss casts in our D&D game. For a long time the arcane focus she used to cast her spells was the weapon she used in the arcane arenas: her chakram. When casting the spell she made the motion of deflecting the incoming attack, which made a cool visual, but also made it look like she was doing it with her weapon, which was useful as early on she was trying to conceal the fact she was a spell caster.