"Prediting the future is not a science, nor is it an art, it is pure guesswork and no-one in history has been able to do it consistently. "
I agree with you on that one.
But like anything else we do in our lifes, approaching the market without a plan is bound to disaster, unless you are one extremly lucky person. Plan is the core of the action. Mapping out the plan that is based on known future events and on understanding of the present (initial) state is something that helps immensly. That is as much one can expect from a good plan. Defining the present state is not an easy task if you do not know, or understand the parameters of the system. As far as I am concerned, being relatively new to the market, an experience and knowledge of some people on this board that share their knowledge, techniques, and thier points of view provides the depth and the wealth that I found to be very helpful.
Nothing is cast in the stone and the plan is bound to changes with future facts like Keynes says "When facts change I change my mind".
Otherwise we'd be lost in woods without compas and direction where to go.
On top of all of that, you better have some luck with you.