It's not about volume, you can write a 1,000 articles and none of them may get indexed by Google or read by anyone.
So Quality counts.
Next you have to write about commercial subjects that have large pools of available advertisers.
Go to Amazon and see what people are buying BEFORE you write about a product. Some people will try to find the most expensive items (which can work sometimes), but you are better off writing about products that people can and will buy online. Who buys a Dishwasher? Amazon has a top list that tells you what people buy.
The next thing you can do is promote your own hubs on other sites (link back to your hubs).
You are not going to get rich, but if you commit to a couple of articles over time you will start to earn enough money to make it worth your while. I've been here 3 years already, athough I don't have time to write much any more.