I only have a personal site but as a result of learning, I hope to eventually make income from it. I have been studying which of my interests that are already on my site are searched the most. I plan to expand on those. So.....what I like and am interested in came first. Fine tuning and featuring certain topics on my site are next. This is how I'm trying to create my niche. It's my understanding that words and phrases with lots of results can also mean lots of competition. Keeping that in mind also helps me to figure out what direction I want to go with my site. I'm just beginning and have a lot to learn but right now, this is my method.