The best thing that you can do to give a project legs is to get other people involved. Even if you don't have someone who can work on coding with you, just sharing it and enrolling other people in your vision for a project is the number one way to give you the motivation to continue working on it.
This is true, the feeling that someone is depending on your work can give you the necessary boost to actually finish, or at least reach a polished enough version.
