Melissa Yu provides advice on improving your data visualization skills:
Common chart clutter items include:
- 
3-dimensional effects 
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Dark gridlines (use soft gray gridlines or eliminate gridlines when possible) 
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Overuse of bright, bold colors 
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Unnecessary use of all uppercase text (uppercase text is only necessary when calling attention to an element) 
Basically, remove every visualization “feature” that Excel 97 gave you…