You’ve planned your project meticulously and know everything that needs to happen from the moment you begin working until the moment you dust your hands and step away from your completed creation. Every detail has been accounted for and all that remains is the labor. Guess what. You still don't know what you’re making.
Sometimes the thing you want to make is different than what your thing wants to be. Give yourself room to explore and let your project develop through the process of creation. What is the project is telling you? Collect feedback while you work and let it inform your decisions. Don't be a slave to feedback and observation but don't resist them, either.
People will view, use, read, hear and taste your creation differently than you. Their experience will be different than your own. You can’t control everything and that’s fine, let yourself be surprised.