If your hair is high porosity, it's all about sealing in moisture.Make sure to use leave-in conditioner or moisturizer, and seal in the moisture with an oil, anytime after wetting your hair.
And unless you know your hair is lacking protein (more on this later), stay away from protein treatments that can make your hair feel dry and stiff. Instead, leave oils and conditioners in a little longer to give your hair more time to absorb moisture. Don't over-apply product or be heavy-handed.
This could be why your hair feels dry! Use heat when applying moisture (steam, warm water, or a heat cap) to open your cuticles.
Since porosity affects how your hair retains moisture, it also affects how you should moisturize your hair.