Fine tune is a phrase that means to make adjustments to perfect or enhance a object or skill.

@Nicholas, thank you

A lovely phrase which means; to make very small changes to something to make it work as well as possible. For the example of a 'brand', whilst the brand is good, there is still some fine-tuning we need to do to make it perfect. For all your English needs check out: https://www.italki.com/www.nickrocke.com :)

对……微调