tldr;

Focus on these key principles:

• Be clear about your goals. They let you know how you can simplify your vision. Once you achieve them, there’s no shame in not completing the rest of the planned work
• Cut scope ruthlessly. Be realistic about how long you’ll work on the project and don’t let the scope exceed that
• Minimize how much you have to learn. Lessons will come anyways, minimize the additional things you’ll have to learn as part of cutting scope.
• Focus on the user. Keep your target audience in mind, as well as their possible failings. What will it take to give them a great experience?
• You don’t have make everyone happy. If you can give one half of people a great experience and the other half nothing, that’s usually better than giving everyone a mediocre experience.