What should I do in between hair washes?

Ok, so I am just going to do an experiment with my hair because I hear you are not supposed to wash it everyday. I think its gross and I feel gross from not washing it, but if it is going to make my hair healthier, then I will have no problem with trying it out. A little bit about my hair...I have an oily scalp around my forehead, above and behind my ears when I do not wash my hair, but it is dry throughout the rest and my hair does not separate from one another if you were to run your fingers through it. I have fine hair, but my hair is very soft and not too dull. I also highlight my hair. In the meantime I have put baby powder in my hair to hide the oil. What should I do in between washes? I use Chi silk infusion before I straighten my hair and it makes my hair very pretty. Also, do you have any shampoo recommendations for someone with dry/highlighted/thin hair. Which type of brush is best to take my natural oils from my scalp to my ends?