HOW TO GET RID OF DANDRUFF!!!

hi guysss, please give me some proven and tested recommendations to get rid of excessive dandruff, and when i say excessive, i mean excessive. like i sometimes wake up in the morning with my pillowcase covered by it. not literally tho but it is a lot. I've been dealing with this problem for months now and i just don't know what to do. there r days in which the dandruffs aren't that noticeable, but there r days like these past few days that it is so noticeable especially when i don't tie my hair up.