Well, to answer this question is actually quite easy and will be difficult to answer it with another hub.  First I sit and look around...and think to myself what would be interesting to write about.  After that fails horribly, I generally look online to find answers to questions that I have or why I have chosen to do, use or follow a specific pattern or practice. 

Sometimes, I even actually think about what I am going to write...but, again that usually is not what I do...I am a spontaneous writer.  Finding, questions or ideas online that need addressing or assistance.  I usually start to write about this idea and let if flow.

So, in short I wing it.