The question should not be "how much traffic" but "how many conversions" you need in order to make more money. What percentage of those 450-650 visits per day either click on an ad, buy something on Amazon, or complete some other desired action? If you're like most people, it's a pretty low percentage -- usually not higher than 10%, and probably more like 1%-2%. That means that whoever doesn't is where you can improve. Experiment with different Hubpages formats, work with different keywords, products in your ads, etc. to see if anything helps raise the conversion rates. Try to think about what someone is likely to do or buy before and after they come to your page, and use that to find them and then help point them in the right direction via links and ads. It's very possible to get 1,000 hits a day with an average of 2 conversions, and just as possible to get 500 hits a day with 100 conversions -- you can see why more traffic doesn't necessarily mean more money.