One of the most comprehensive tools for finding reviews.
For reviews close to the opening date of the film, make sure to pay attention to publication dates of reviews.
Who is the critic? Are they at least a professional writer? Critics' names link to their professional information and affiliations.
Metacritic is a bit sketchy because it offers professional reviews alongside random commentors like Butterballer1, Goddessof_blah, dawdlingpoet, and imthenoob who are everyday people who simply like to share their opinions about movies.
Stick to content in the left side column for reviews written by professional newspaper staff writers.