First off choose a topic that you are either knowledgeable about or willing to research to some degree of depth. And also try to make it a topic that is interesting to both you and, hopefully, to your intended audience.
Next write the actual text of the hub. I find it's best to segment my hubs into sections including an intro, several body paragraphs and a conclusion that sums up what I wrote about and what I intended to convey.
It's a good idea to insert images or video capsules in between text capsules. Try to use images that either fit the subject matter or are at least funny or interesting.
Leave links to other hubs, sources for your information, etc where applicable. And decide whether or not to allow ads in your hub. Personally I'm not here to make money I'm here to engage with others and express my own opinions in article form so most of my hubs have ads disabled, but if you're looking to monetize you're going to want ads.
So those are my tips. Enjoy your stay at hubpages!