Shape it up
Building something complex is very tough. Everything any person decides to build should have a visible or understandable finish line. Otherwise, creating might take ages and burn out even very solid personalities.
In most cases, building software is one of the hardest tasks, just because drawing a final line is unattainable. New features keep coming during the building process. The logic of the product might be changed due to architectural restrictions. Many other reasons might appear during the process.
There are a lot of methodologies and approaches to avoid that during the development process. Just name it: Kanban, Scrum, Agile, etc. Any of them has pros and cons. But each of them requires the whole team to get involved in the methodology, have an understanding of it, and solid management to keep it working.
The best approach to working practically without any restrictions, named "Shape Up" by Ryan Singer, was invented in Base Camp – a web app for work management.
The basic idea is not to have everything described or discussed before starting building, but to shape each feature into an achievable and tangible version. Then the team works on their own to build the features.
The approach is easy to implement for any team and very easy to manage and keep track.
A short book of the same name is available for free on the Basecamp website – https://basecamp.com/shapeup. It takes a few hours to read and a few more days to give it a try on some parts of your development path. And it makes you never worry again about making the whole team easy-going.