Write good quality articles Vince, ones that help your readers and will stand the test of time if possible. Be consistent, build up your core of good quality hubs and in time your income should increase. Learn as much as you can from established HP authors with regards to quality, SEO and promotion.
Not all of your hubs will earn on a regular basis. The ratio on average is something like: 80% of your income will come from 20% of your hubs. Give or take a few percentage points. I find this to be more or less correct for me personally.
The bottom line is, keep creating helpful, well written articles.