Building a business off of data

I have a collection of tools that collect data. I have heard of businesses selling data. I would like to be able to do something like this. However, I have no idea what a business model around data looks like. How do you appraise the value of your data? How do you identify customers? I recognize these are very generic questions. But any insights would be appreciated.

I currently datamine poker hand histories and sell data.
For us the value of our data was easy to assess because we directly make people way more money who play online poker so my approach would be how much monetary value does your data give your customers and then what would be a fair % slice of that. So if you think on average your data will add $1,000/mo of value to your customers it might be fair to take 10% of that so $100/mo. This obviously depends on the industry.

The more processed and informative the data is as well the more you can charge for it. With our poker hands we sell the raw data very cheap and the processed data at more expensive prices as its more valuable and more resources have gone into producing it.

The business model we use is depending on what limit you play it costs more and the more data you want the more it costs. The first point in other industries would be something like "the more employees you have the more it costs as you have more money" and the second point is "if you want more searches, more statistics and more detailed reports" it will cost more.

You could probably find some interesting insights about building a business off data from this episode of This Week in Startups: http://thisweekin.com/thisweekin-startups/this-week-in-startups-106-gil-elbaz-founder-of-factual-com/ Blurb: "This Week in Startups has an amazing guest this week. We’re sitting down with Gil Elbaz the Founder of Factual.com to discuss his new project. BTW his old project was this little old thing called Applied Semantics which Google Bought and turned into Adsense. You Definitely want to hear what he has to say."