The default column width in Excel is pretty narrow, and the location to change it is not very straightforward. It took me a long time to find so I thought I would throw a quick step by step on here with pictures.
Here is the bar chart with the narrow widths that I want to make larger:
Under Series Options there are settings called Series Overlap and Gap Width, these are the settings you can tweak to get your desired bar graph size and thickness.
Making the bars fatter is what I wanted to accomplish so that they stand out more so I will stop here but fiddle around with the options in format to get your desired bar settings.