Timeline. Four Easy Visualization Mistakes to Avoid. Creating a great visualization is not as hard as it seems. Provided you have some interesting data and an effective tool with which to visualize it, a little bit of thoughtful design will lead to a decent result. That said, there are some mistakes that are very easy to make, but can ruin even a thoughtfully-made piece. Here are four data visualization mistakes you should avoid. 1. Serving the Presentation Without the Data.