Being too focused on earnings is the fastest way to make your revenue fall even faster. I know because it kills my passion for writing. A few years ago, I wrote for the fun of writing, without any thought of making money. Those articles in my websites are now giving me a decent amount of money every month. Why then do I join HubPages? To earn even more, of course, LOL.
The only way to earn more income is to write as much as possible, for we never know which one would hit the jackpot one day. Many are the bestsellers that have been rejected many times before they were finally published. An example would be "Zen and the Art of Motorcycle Maintenance". The novel entered the Guinness Book of Records for being rejected by 121 publishers. It subsequently sold more than 5 million copies worldwide. Just imagine even if it's only $1 a copy in royalty!!!
Stephen King threw the first 3 pages of his short story, "Carrie", into the wastepaper basket. His wife fished them out of the garbage and encouraged him to finish the story. He followed her advice and turned it into his first published novel. The rest, as they say, is history, launching King's career as an established author.
Bottom line is we never can know whether a hub is going to hit the jackpot. The only thing I know is anything written with great passion stands a great chance of making money, if not today, maybe 3 years down the road. So think far, and not follow your daily earnings like a stock market, LOL.