You can find more of the best practices here. These best practices are very important because some issues might cause performance degradation. You might be surprised how applying some of these best practices might improve the performance of your workload.
The last item that is related to schema optimization is sometimes hard to check. You would need to look at your schema, inspect all columns and find what to optimize. If you have a large schema, this might not be an easy task. But you can make your life easier if you use the QPI helper library that can detect schema issues for you.
Read on to see what it can find.