Is there a really effective way to whiten skin?

Lately, I feel like my skin tone has become dull... I went on a trip and it got darker.

I'm so curious about how to get whiter skin, so I'm posting this!! I've tried whitening products and packs, but I don't feel much of an effect. ㅠㅠ

So, is lifestyle more important for whitening skin? Or am I diligently using sunscreen and moisturizing products, but I would like to ask for advice from those who have personally seen the effects of whitening skin!