Tactile charts are widely used by blind people to get access to visual charts. They are often a transcription of visual charts. However, design guidelines for tactile charts are not sufficient for effective tactile chart design. An effective design supports the reader understanding the chart's underlying data. We explore how design can improve the readability of tactile charts and can support the user by getting insights from the data. We analyzed 69 tactile charts, including bar charts, line charts, pie charts, area charts, and scatter plots. The charts are taken from publications, guidelines and transcriber's institutes. In particular, we studied how axes and tick marks are designed and how labels and legends are used. Furthermore, we looked into the style of chart elements as well as design considerations for specific chart types. Based on the findings, we derived basic design guidelines for bar charts. The presented study is the first stage of our research which aims to develop design guidelines for tactile charts.