Honestly, the variables are nearly endless, key words, links, back links, all these can help; but, when it comes down to it, my advice is to write what you love, what you have a passion for, and let that passion show through in your writing. Let your passion be your driving force for developing your writing and in time the money will start to come in. Hub Pages is not a get rich quick opportunity. Those who have been making great money are those who have been at it for several years, have hundreds of Hubs, and most importantly - Stayed the Course.
"Winners never Quit, and Quitters can never win!"