Creating a game is a huge project. You are going to spend tens of hours without the feeling of any progress. The only way how to preserve is by working on something you like. Don't do a game you think people will enjoy, do a game you would enjoy. If it is good, people with similar taste to yours will find it.
Decide the theme of the game: which feeling should players have while playing it. Now decide the type of the game (platformer, VN, rpg...), think about which gimmicks you want the game to have. With gimmicks, I mean in-game mechanics, music, art style, story, dialogues, etc. All gimmicks should support the theme of the game, if it doesn't, think twice if you need it. Don't add too many features to the game, or you will never complete it.
What are your strengths and weaknesses? Are you familiar with art, programming, story writing? Start with what you are the most familiar, it is much easier to recruit people to a project which already has some content, than to a new, blank project.