duìyú对于emphasizes the target while guānyú关于 emphasizes the relevant elements.
For example,
对于那个人，我不了解
Duìyú nàgè rén， wǒ bùliǎojiě
About that guy I not familiar with
‘I don’t know much about that guy’.
关于这件礼物，有一个感人的故事
Guānyú zhèjiàn lǐwù， yǒuyīgè gǎnrénde gùshi
About this gift has a moving story
‘There is a moving story about this gift.’
