There are many ways of monitoring SQL Server pressure. Here is a quick demo.
When you have dozens of databases hosted in a single instance, it helps to narrow down on databases that are contributing towards maximum IO reads and writes. In other words we are trying to narrow down on databases that are consuming maximum IO.
Even with the fastest of CPUs and Storage, Page Splits are still very bad. Also leads to fragmentation. Here is a quick video that shows how you can capture page splits using extended events.
Age old topic but still very important even in the age of SSDs. Watch the demo.