Most product-development managers are always struggling to bring in projects on time and on budget. They never have enough resources to get the job done, and their bosses demand predictable schedules and deliverables. For this, you may need a lean software development software development process, as poor implementation could be the last nail in the coffin for your project.
Don't marry your ideas, think like an investor, remain objective, but don't lose your passion. Data is your guide. Get in the habit of using your own product on a daily or weekly basis. This way you're putting yourself in your user's shoes and will be able to spot problems early on.