Bar and Column charts are possibly the most common charts used in business intelligence today, second only to line charts. It is therefore important to understand the benefits of these types of charts, and also to appreciate what it is that these charts do best and how best to use them.
When first learning how to construct a chart, most school children begin with bar charts and line charts. As a result of this, many people view these two separate methods of displaying data as somewhat interchangeable. This is a mistake however. Line charts are best suited to displaying trends. This is something that makes obvious sense once stated. The trajectory of the line, up or down, gives you clear information on how a specific data point progressed over time. Bar and column charts however are not trend charts. Instead they are used for comparison, allowing different data points to be shown in clear contrast to each other.
When displaying contrasting sets of data, another option that can potentially be taken advantage of with bar charts is a target/actual display. This allows you to show the target result for a particular point of information, and the actual figures achieved. This can be done by overlapping the bars in a bar chart. When using this approach, it is important to ensure that both bars or columns are clearly visible. One way to do this is to make the columns different widths. In this way it is very clear where each column ends. Colour choice is also important here.
As always, you should avoid overusing text. Make sure that any necessary labels are clearly visible, but also ensure that they are not overlarge and that they aren't too brightly coloured. This feature should be there when required, but should not dominate the chart. Finally a word on colour - when choosing a colour scheme, try to keep a single data set the same colour. This will enhance the clarity of your finished product.