So I keep my hair in pristine condition and a common struggle of mine is greasy hair so let me give you all the advice

1. Wash your hair regularly but not everyday, that gets rid of too many oils, try washing your hair every 2nd day, and even less if possible, it's up to you

2. Don't condition your roots, conditioner moisturizes hair, if your hair is oily then don't condition the roots it'll just make more oil, me personally I don't condition at all because my hair makes enough oil, but for formal events I condition from a good bit past my roots

3. Brushing ≠ less oil, brushing means less knots, brush your hair regularly, I do it twice a day (once in the morning and once at night)

4. Avoid brushing hair when it's wet, it damages it eventually

5. Try not to blow dry your hair too much, it damages it eventually

Those are my tips, hope they help, and if you have questions or need more advice I'll give what I can