Most financial or scientific data slides gave all visual elements equal weight.
- The big trend in the data (a declining line for example)
- The amounts are in EUR million
- The explanation that 2010 includes France
- The fact that 2011 results are still unaudited
- The source of the market data
- All data is to be treated confidential
This is not how the novice discovers your data. Make the first order element pop out, so people get the message without the clutter of all the other information.
For the 2nd, 3rd order elements you can use smaller fonts, or - what I find most effective - use light grey font colors. Another options is to put a long wordy foot note at the bottom of the chart that has all the other bits in it, thereby avoiding the need to populate the slide with scattered text labels.
After people get the message and have questions they will look for more information and find everything they need.