The best advice I can give to you is to gain a thorough understanding of the problem you are trying to solve. Ask yourself as much questions as possible and try to find satisfying answers.
For a start:
- What is the kind of data you are visualising?
- What attributes does the data have?
- Which relations in the data are important?
- How will the data be used?
- What kind of insights does the user want from the data?
There are many more possible questions. Try to really understand the problem before spending too much time on specific solutions or design decisions.
You seem to have settled on a bar chart now, but another type of chart could be more appropriate. Maybe a bubble map chart or a bar chart on a map. I have no idea at this point, but you will find out soon enough once you research the problem.
I know a pretty generic answer, I cannot be more specific without knowing more about the problem.