Design changes a normal chart into a good chart. Time spend on design will improve readability and improve attention and information transfer. Use design to give the reader context or guide them to your conclusion.
Charts are about data, axis only assist
Charts are made to communicate data, so it is important that the attention of the reader goes to the data. You can improve this by making the axis grey instead of black. The same goes for the ax labels.
Do not use more then four series
The human brain cannot process more then four different things at the same time. Try to limit your chart to four series. If you have more, think of a way to reduce them, or create multiple charts. (See enhancement Small Multiples).
Highlight what is important
Make your reader see quickly what you find most relevant or important in your chart.
Apply relevant ranking
Ranking you bars in the most relevant order, will give the reader more information about the context of the data. Ranking it according to the alphabet is hardly ever the most important context.
Column or barchart, start your axis at zero
When you create a column or barchart, make sure your axis start at zero. You reader will scan the chart and draw conclusions based on the different lengths of you bars. If the bars are cut of, the reader will come to the wrong conclusion.