Don Eskridge, the designer of The Resistance, answers questions on Reddit. Here’s some of his advice for aspiring designers:
I suggest not designing for what will sell, but what you enjoy. If you do and then get to the point that you really, really, really like it, then’s the time to think about publication/whether it could sell.
To that end, you will probably have to mercilessly simplify the game, which will probably benefit it in the end. Amazing how many house rules get made in a house with friends. To do that just think, “What’s fun about my game?” Get your friends to tell you. Then get rid of everything that’s chrome (unnecessary/overly thematic rules) and try to even get rid of rules you thought were completely necessary but never tried living without.
You’ll be surprised how it’s possible to identify the fun through this sort of design surgery. Then streamline everything to that. Resistance has just two major mechanics: voting and sabotaging. Once upon a time there was more but they didn’t strengthen these core fun elements, so off they went. You can do that too.