If you suffer from dandruff, I read that alternating between Neutrogena T-Gel and Head & Shoulders is the best tried-and-true scaly scalp remedy, but if you hesitate to put chemicals on your head, you can try a few folk remedies that the organically-prone recommend:
1. Brush hair thoroughly before shampooing. A vigorous brushing will loosen dandruff and promote a healthy scalp. The distribution of your scalp's natural oils is also good for hair.
2. Apple cider vinegar is supposedly good for the scalp. Mix in one part apple cider vinegar with one part water (my best guess is one cup of each). Once you've shampooed, apply the mixture to scalp, massaging in. Do not rinse. Towel dry hair and let the mixture dry onto scalp. Rinse 8-10 hours later. You can also place undiluted apple cider vinegar onto scalp. Let it dry and rinse 2 hours later.
3. Massage coconut oil into scalp, shampoo, then rinse. Keep this up until the dandruff clears up. My instinct says this will cause really greasy hair, but some people swear by coconut oil. I suggest avoiding this if you have oily hair and trying something else. It might be great for people with dry hair.
I haven't tried any of the above remedies so I can't personally vouch for any of them, but I had to share them with you in case you want to try them and weigh in below.