Not sure if you already completed the work. You need to make sure the bars all have the same width and pick a scale that allows the smallest bar and biggest bar to both fit and be easily seen. Pick unique colors that make it easy to identify things. Have keys telling you what the bars mean.
Excel is the easiest way to make one, but if you are doing it by hand, you might want to use graphing paper to help you. Lots of good Excel tutorials online, like