First and further most, a solid, trustworthy and sincere project staffs/team especially the manager. This is very important because they holds the greatest impact of the project, yes community also but how the staffs handle everything is the foundation. It's not hard for the community to trust if the management is working good. For the whitepaper, they say uniqueness of the project is a plus for investors but for me it's the consistency. We are humans and consitency is rare to us but with a great team, it can happen. Roadmap is also important because it is the flow of the project and how it goes will affect everything. Just like learning something, it should be a step by step analyzation.