Not really a game designer myself, but one thing I've heard is to make a bunch of really small game projects, rapidly trying out ideas without over-investing in them. You might stumble onto something interesting, and then you can expand it if you think it'll be worthwhile. I hear game jams are good for this, and IIRC, the first version of Terra Nil was created during one.
This is really great info!! Thanks a bunch for the reply. I have been looking to physical card and board games as a means to understand what it means to "find the fun" when it comes to game design, it's not as obvious as it is when I'm trying to learn a new programming language. I have been eyeing some game jams for a while and I need to make time to actually join one because I hear many people say how much great experience those are. Thanks again!!