The opposite of faith is not doubt. The opposite of faith is certainty.
Faith is probably best looked at (and practiced) as if it were a verb--practicing, developing, living. I do not "have" it, or possess it, as a system of religious beliefs, handed to me or even accepted whole, complete, by me at a point in time. Instead, I reside, in active living, in active questioning, in that place where faith "lives" and develops in directions that surely will be different next year than today.
I have faith that faith requires my active participation, not my passive acceptance; and that faith will always recognize uncertainties and understand that doubt is part of faith--even drives it. Otherwise, certainty is the easy way and leaves less room for faith.
I have faith that faith is an effervescent bubbling up from a deep place that is connected to the core of the Universe and all that exists. My project is to live in that Fountain.
Today, I am "faithing"--may it always be so.