Any guidelines for bleaching black hair?

Use proper product which will suits your hair.

I used to have bleached hair. And I coloured it black again. I went to the salon to have bleach, my hairdresser told me that if I want to lighten it, I need to have light brown coloured first as my hair is pretty damaged from the previous chemical I been using. He also advised to take Niveau Labs krill oil and flaxseed oil. So I ordered online, and I am taking it for more than two weeks now.And I am surprised how it made my hair much softer, thicker and stronger.