Principles we want to keep in mind:
- Show the data without distortion
- Use color, shape, and location to encourage comparisons
- Minimize visual clutter (maximize your information to ink ratio)
The two questions you want to ask yourself before getting started are:
- What type of variable(s) am I plotting?
- What comparison do I want to make salient for the viewer (possibly myself)?
Figuring out how to highlight a comparison and include relevant variables usually benefits from sketching the plot out first.