Tips For An Aspiring Game Creator?

I have my game engines downloaded, waiting for the fuel of ideas to fill it up. The plans, the framework, the story, the characters, and so on. It will take time. I know that in order to have good sales for a game, I need a lot of factors to consider. Things such as niche, game mechanics, and so on. I am new to online marketing, and I might choose online campaigns as my main source of advertising.

Based on your evaluation on the games that sell, what would "catch" the crowd.? For the PC, I am seeing more survival/crafting games, for mobile...we have Clash of Clans. I am choosing either PC or Android for my game. I am asking the forums on your point of view on what would sell. It can be either market based or based personally. All inputs greatly appreciated! ^^