Creating high performing reports with rich calculations is a critical but good report design can improve user adoption and reduce confusion. There is little worse than no one using your reports. Here are some practices and references to create great looking reports.

Know your audience - do the users want an at a glance status report or are they going to want patterns and insights? The same dataset can meet both needs but the layout of both reports is very different.

Why is the report needed? What questions are you answering and what is the key message or question you are addressing?

Metrics > Data

Data are numbers like Sales Revenue and gives a bit of information, but % Change in Sales Revenue from Last Month is the start of a story.
Good metrics take the raw data and describe it.

Comparing data against a prior period shows direction.

Variance from a target or goal shows how we are meeting expectations.

How to communicate the information, or even to wonder what use a Pie chart is? Selecting the right visual is half art but also half science.

Report design
Examples
Lecture

Designing effective reports This is a new course on the Microsoft Learn site that covers effective report design from some of the best!