pull requests – Tips for more effective PR reviews

My team of 4 devs is a steward of a large UI application where on a weekly basis, at least 2-3 other teams are making changes. I am inundated daily with 4-5 fairly large PR’s, and even if they break their PR’s up, the volume is still very large. I feel like I’m either spending most of my day reviewing PR’s, or I’m not doing a through job.

Do you have any tips on making PR’s more efficient and effective in a way that prioritizes quality feedback?