The interface in SaaS products is directly the product itself. The user does their job on these screens; hence, the success of a dashboard design goes from 'beauty' to more 'day-long usability'.
The basis of a good panel is the hierarchy of information. The most critical metrics should be seen at first glance, secondary details should stay one click away. A screen that tries to show everything at the same time shows nothing.
Data tables are the heart of SaaS design. Alignment, number formatting, sorting and filtering are details that determine scanability. Right-aligned numbers, consistent decimal, and smart color coding make a table readable or unreadable.
The part that most designs skip is empty and error states. A good 'empty state' set up for a user who doesn't have data yet saves the first experience. Dark/open theme consistency and a scalable component system won't slow down your team as the product grows.
We designed a lot of data-intensive products, from crypto panels to enterprise ERP interfaces; my common principle has always been the same: to hide complexity from the user, not to run away from it.