1. original, quality content - this means you actually have to write something. Google loves words, so the more content you have in your hubs, the more people will find them and read.
2. spelling and correct grammar - check your hub for spelling mistakes and proper wording - their instead of there, to and two instead of too. If you have trouble with these, I would suggest writing your hub in Word first as that program will catch more of these errors than HubPages. As an example, "What make an hub to quality of hubpages?" should read something like this: "What makes a quality hub on HubPages?" See the difference?
3. format your hubs - make use of the different capsules HubPages provides. These help you to add good, relevant content that people are looking for. Most people enjoy reading well thought out hubs with good information.