Don’t use the Visual Designer, write your queries out first
As tempting as it can be to drop and drag fields and parameters into your dataset, I would not recommend it. It makes it harder to repeatedly test, share the logic in the query, and see the results. Instead, write the script, whether it be in DAX or SQL. Writing the queries is a faster process that gives you a lot more control over your queries. If you don’t understand SQL or DAX to a proficient enough level, don’t panic, you could start the query with the visual designer and then convert it to the script.
When you’re running your DAX queries, don’t use the dataset query designer in the report builder, use DAX studio. DAX studio gives you the ability to efficiently query, format, and test DAX. As an experience it’s much faster and easier to show other people. If you are using SQL queries you could use SQL Server Management studio.
As a practice, when you’re trying to test the data, it’s important to get the data right in your queries before you place that data in your report.
Read on for the rest of the tips.