2. Change Your Fucking Idea. You have 6 months to figure out if this is a good idea and there's a very objective test: you are growing rapidly on revenue and/or users. If that is not the case then pull the fucking plug while you have time. Do not worry about what investors will think. Do not worry about what anyone will think. Better to have been the guy that changed his idea and succeeded than the guy who didn't and failed. Sticking with a failed idea is the dumbest thing you can do.
3. Make money. Consumer startups that will make money "later" are for people who are really lucky, happy to fail, or already rich. Creating a business whose primary objective is to earn revenue makes it extremely easy to know if you're succeeding or not. Either you're profitable or you are not. If you are not then you are still failing.
4. Do simple businesses in industries you understand. Stick to what you're good at. Spent 10 years in finance? Create a damn finance product. Used to be a doctor? Do something in medicine. Solve a real problem you had or have in the field you have the most passion and experience for.
5. Keep up development momentum. Do not let more than a day or two go by without improving the product. Don't let anything get in the way of you improving the product. Don't let old decisions block forward momentum. If you have to temporarily make the product worse in order to keep going, then just take the hit. You can't afford to stagnate on product development.
6. If you have money then hire people that are good. When you hire good people you should be saying to yourself "Holy shit, I don't know what we would have done without <person>". Be unapologetic about having people do things you're bad at. Make people work hard. Hold yourself to a high standard and everyone else too. Better to be a hardass that succeeds than a softy that fails.