A chart is always an answer to an underlying question. If you don’t know the question be prepared for random answers (300-slide Powerpoint presentations, anyone?).
Do yourself a favor and and write down the questions that define your project. Group them meaningfully and use them as chart titles. Each chart may prove irrelevant or force new questions. Write them down. Repeat the process.
Jacques Bertin tells us that a chart should be able to answer elementary (“how much did we sell in March?”), intermediate (“what happened in the North district?”) and global (“how does our product compares with the market?”) questions. If it doesn’t, then it is an inefficient construction and should be redesigned or removed. This is also a simple way to identify redundant charts.
Don’t replace information overload with chart overload. Similar questions may require a single answer. Create a single, interactive chart and let the users find their own answers.
Embrace the questions, delegate the answers.