General Brazilian
apertar os critérios
most commonly used in both formal and informal contexts
São Paulo
apertar os critérios / enrijecer os critérios
both forms are used, with enrijecer being more formal
Portugal
apertar os critérios / endurecer os critérios
endurecer is also commonly used in formal Portuguese
Rio de Janeiro
apertar os critérios
standard usage, occasionally 'ficar mais rígido'