If ever there were an easy tip to follow, it's this: Do less.
To be more specific, wash less often. Every day is too much, since shampooing tends to strip hair of the natural oils that make it lustrous and smooth. If you have dry hair, this is especially damaging.
Keep hair shiny and sleek (and healthy!) by washing it only a few times a week. You'll notice a more Kate-ish appearance immediately.
It does matter, of course, what you wash your hair with …