How to Improve at Reviewing PRs?

I've recently joined a new company and I've begun to realize that I had never previously been exposed to good PRs and general peer review. My colleagues seem able to pick up on many details that could be improved in each others' and my code. These range from minor comments about docstrings, variable names to more general comments about the philosophy of the codebase and particular function implementations. Whereas I find it hard to pick up on anywhere near the same amount of detail. Are there any good resources out there on how to achieve a thorough review, akin to the resources available on how to read a scientific paper? Any tips from the community?