it depends on how loyal you want your investors to be, the first thing to do is to make the project attractive, to have some people who really know what they are doing in important positions and to have constant people in their work who take care of the project, obviously you have to have the essential thing that are the whitepaper, the roadmap and the use of the project ready before launching something, try to comply with the deadlines in the established time since an extension looks bad at the eye of the investor, and choose well by what means you want to spread your ICO (airdrops, bounties, marketing).