All I have ever done is write on subjects that I am interested in or know about. The former I do plenty of research on for before I write them, the latter I already know about from my own knowledge and experiences. Most of my hub titles answer questions, so the titles end in a '?', and the title will begin with words like, 'what, why, where, how' etc. I also have written a hub on 'The Main Mistakes New Hubbers Make' which is full of things I avoid doing, and hopefully helps guide newbie hubbers.
One way or the other I guess I must be doing something right and am not complaining right now 