docs: Add troubleshooting instructions for pre-aggregation matching

Author: igorlukanin

docs/pages/product/caching/matching-pre-aggregations.mdx

@@ -91,7 +91,15 @@ cubes involved in the query.
 - If multiple cubes are referenced in the query, the pre-aggregation should
 include only members of these cubes.
 
-## Common pitfalls
+## Troubleshooting
+
+If you're not sure why a query does not match a pre-aggregation, try to identify
+the part of the query that prevents it from matching. You can do that by
+removing measures, dimensions, filters, etc. from your query until it matches.
+Then, refer to the [matching algorithm](#matching-algorithm) and [common
+pitfalls](#common-pitfalls) to understand why that part was an issue.
+
+### Common pitfalls
 
 - Most commonly, a query would not match a pre-aggregation because they contain
 [non-additive measures][ref-measure-additivity]. See [this