My first tip would be to spend some time planning it, considering how and what you are intending to use your boat for. Are you going to use your boat solo or tandem, on open or white water, for short trips or expeditions? All of these have certain common elements but also have very different needs. Have a look around at other boats you may have seen or used, and see what others have done, then ask yourself if it will suit your intended use. Remember just because it works for one person doesn’t necessarily mean it will work for you!