Comedy isn't a funny thing, it's simply learning to laugh at the crap we go through in life. Give people a way of looking at things that most have experienced that will make them chuckle, and you win.
Comedy, like good acting, is one of those things that requires the mind-set of being a near perpetual student that constantly studies the classics as well as the contemporary -- those other comics that were leaders in the industry all the way around as well as the live show setting where they can see where and why the bad comics fail. As with all facets of "art" one must be brutally honest and realistic when it comes to the self and more importantly ACTIVE when it comes to the lessons to be learned.
Books can't teach you comedy they can only give you concepts and theory. In order to swim you must jump into the pool, preferably on the deep end when you'll either swim for your life or drown -- half-measures simply don't hack it. So get involved with a local improv group, the local theater and even classes/workshops that will help you gain experience not just in comedy but simply being on stage and able to take that pie in the face.
NOTE: Spending a few months at the Ringling Clown College might be a good bit of foundation as well, depending on how slap-stick you wish to go in your comedic expression, look at Robin Williams and some of the other physical comics and how their antics mimic classic clowning.