Dot the i's and cross the t's

Dot the i's and cross the t's: fazer as coisas com muito cuidado, certificando-de que não há erros (pingar os “Is” e cortar os “Ts”)

 “I've nearly finished the report. I just have to go over it once more to dot the i's and cross the t's.”(www.englishclub.com)
i i i i
t t t t