After and indecent amount of research for how to become a better writer, it all came down to something like this. You just have to write. No matter what it is, just continue to write. Sure there are different little things you can try as well, but this is the main thing you must do.
Prompts are one of the best ways to find topics to talk about, so that you are able to variate your writing. There are plenty of places where you are able to find prompts, such as Daily Post or /r/WritingPrompts from Reddit.
Enjoy what unfolds from my mind.