More to the point, what is your skillset? By this I mean are you good at working with timber? good with grp (fiberglass) or epoxy? You have to ask yourself what you would be happy working with, then plan your build around those mediums.
For instance if you know grp inside out, then you would know which materials to build the plug from to lay up a mould to lay up the final hull. If its timber then reading up on how to produce the frames to add the outer cladding to is the next step. etc etc etc.
THE MOST IMPORTANT step, by far is to remember, if you get stuck don't be afraid to ask a question!