Lillia's core strength is her exceptional movement speed, empowered by her passive. Use it to constantly harass and kite enemies.
Her early damage is weak, but she becomes powerful with core AP items like Liandry's Anguish. Focus on consistent farming to accelerate her growth.
She is a very strong AP jungler in teamfights but can be challenging in solo queue. She can also be played top, kiting and harassing melee champions.